Heart of the Storm

by Sonny13

Hartley had made a living on impossible heroes and faraway places, she'd grown up daydreaming and wishing for the days when she could be living her adventures, instead of just writing about them. But when the chance to run far, far away from her boring old life is dropped in her lap, is it something she has the courage to do? And who exactly is The Heart? Eventual Doctor/OC

36. The Lazarus Experiment

A/N: This one's dedicated to the awesome OodDude, who sent me the greatest message/review ever. It made my entire week, and she's the reason this one's out today instead of later in the week – her kind words gave me the motivation to finish it up ASAP.

OodDude – I sincerely hope you, and everyone else reading this, enjoy reading it as much as I loved writing it!

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THE LAZARUS EXPERIMENT

"For those who have crossed, with direct eyes, to death's other Kingdom,

remember us – if at all – not as lost, violent souls, but only as the hollow men."

T.S. Eliot

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"Hold that there!" the Doctor's voice shouted over the familiar groans of the TARDIS.

"This?!" Hartley shouted back, holding her hand above an important looking lever. He nodded, and she quickly held the lever in the downward position.

"What can I do?!" Martha asked, leaning with the tilt of the ship to keep herself upright.

But the Doctor didn't answer, probably because he didn't have the time to spare. "We're coming in hot!" he cried, hands moving so fast they nearly blurred.

The whole room shuddered, the grating of the floor rattling beneath their feet. Then the ship finally landed with a familiar, comforting bong and everything fell silent.

"There we go! Perfect landing!" the Doctor crowed. Hartley stepped away from the controls, rolling her eyes and absentmindedly stretching out her knuckles. "Which isn't easy in such a tight spot," he added an undertone. Martha was practically bouncing on the spot in her excitement.

"You should be used to tight spots by now," she said playfully before glancing to the door. "Where are we?" she asked eagerly, barely able to contain herself, her enthusiasm thrumming for their next big adventure.

"The end of the line," the Doctor said rather ominously, and the smile dropped from Hartley's face, replaced by a frown of suspicion. Martha didn't seem to notice, scurrying down the ramp and pausing at the doors, grinning back at the Time Lord in excitement. "No place like it," he assured her, nodding for her to go through.

Martha darted out the doors and the Doctor stuck his hands in his pockets, following after her at a much slower pace. Confused, Hartley pulled the cuffs of her cardigan down over her hands, balling them in her fists as she followed him down to the doors, nearly bumping into his back when he had yet to move out of the doorway.

"Home?" Martha's voice was flat, full of an estranged disbelief. Hartley pressed at the Doctor's back, gently pushing him across the room more and giving her space to move. Once he'd shifted out of the way Hartley saw they were indeed in a London flat. It was small, hardly any space to speak of, with laundry drying off to the side and a stack of crumpled magazines on the coffee table. "You took me home?" Martha felt cut, and Hartley's insides wobbled with empathy.

The Doctor hadn't even consulted her, he'd just decided on his own that it was time for their journey with Martha to end.

It was technically his right – what with it being his TARDIS and all – but she'd thought that they'd been something of a team as of late. It hurt that he hadn't spoken with her before making a decision, especially when he knew how it would upset her – because of course he'd have known. He may have been oblivious, but he wasn't an idiot.

"Back to the morning after we left, so you've only been gone about twelve hours," he told her proudly. "No time at all, really."

"But all the stuff we've done – Shakespeare, New New York, old New York?" Martha said confusion swimming in her head. The Doctor casually perused the family photos Martha had lined up on the shelves along the wall and Hartley leant back against the smooth, warm wood of the TARDIS, watching everything with a frown tugging at her brow.

"Yep, all in one night, relatively speaking," the Doctor continued cheerfully. "Everything should be just as it was. Books, CDs...laundry," he trailed off, swiping a pair of drying knickers off the line, holding them up with an impish glint to his eyes that Hartley hadn't expected. She couldn't help but snort when Martha yanked them back, cheeks warm with mortification. "So, back where you were, as promised," he finished blithely.

Martha turned to look at Hartley, as though sure the other woman would come to her defence and argue for her to stay. But Hartley said nothing, torn between her undying loyalty to the Doctor and her fondness for her new friend. Martha's shoulders slumped in disappointment.

"This is it?" she asked, eyes flickering between them, clinging stubbornly onto hope.

"Yeah," the Doctor nodded, giving a thoughtless shrug. He glanced up to meet Hartley's eyes, nodding subtly to the time machine she was leaning against. She frowned at him in disapproval and the resolve in his eyes wavered. "We should probably, uh..." he trailed off, awkward and uncomfortable.

From the corner of the room came a ringing, then the recorded sound of Martha's voice cheerfully proclaimed, "Hi, I'm out. Leave a message!"

"I'm sorry," Martha herself apologised, but Hartley waved her off.

"Martha, are you there? Pick it up, will you?" It was an older woman's voice, one that was strangely familiar, as if she'd heard it somewhere before.

"It's Mum," Martha explained, and Hartley remembered the night they'd taken her from – only twelve hours the night before, in linear time – when she'd listened to the poor woman's family screaming up a storm in the middle of the street. Not the best first impression, but Hartley didn't like to judge people without getting to know them. "It'll wait," Martha added stiltedly, and the Doctor grinned at the awkwardness that followed.

"All right then, pretend that you're out if you like. I was only calling to say that your sister's on TV. On the news of all things. Just thought you might be interested," Martha's mother said flatly. The machine cut off with a click, leaving them in a pregnant silence.

Bemused, Martha hurriedly turned on her TV to reveal an old, weathered man standing before a hoard of cameras. A pretty young woman who could only be Martha's sister was standing stoically beside him, the picture of professionalism.

"Tonight, I will demonstrate a device which will redefine our world," the aged man was telling the reporters in a croaking voice.

"She's got a new job. PR for some research lab," Martha explained it to them in an undertone, then fell silent so they could hear the rest.

"With the push of a single button, I will change what it means to be human!" the old man proclaimed importantly.

The reporters all began to clamour over one another in an effort to get a quote, but Martha had lost interest, switching the television off again and turning to the pair of travellers with a shy sort of smile. "Sorry. You were saying, we should..." she trailed off, hope and sadness warring in her heart.

"Yes, yes, we should..." the Doctor was distracted, still staring at the television.

Clearly something had interested him, and now that Hartley thought back to the interview, she realised it did sound rather odd. What had the man meant by his comment? Change what it means to be human? Was it just scientific propaganda, or was there something more sinister at play?

"One trip is what we said," the Doctor continued, getting back on track.

"Yeah. I suppose things just kind of escalated," Martha said. Hartley knew she wasn't imagining the way she swayed into him, drifting closer as though she simply couldn't help it. It made an unnamed emotion coil in Hartley's belly, something simultaneously hot and icy. She felt the responding frown curl at her lips and looked away to hide the expression.

"Mmm. Seems to happen to me a lot," he agreed with a wry sort of smirk that Hartley realised made his eyes seem to glitter.

Martha was quiet for a moment, letting her eyes meet the Doctor's in the silence. "Thank you," she told him sincerely, and Hartley warmed to her again. "Both of you," she added, turning to include the strawberry-blonde traveller in her gratitude, "for everything."

The Doctor grinned. "It was my pleasure," he told her emphatically, smiling a final time before slipping past them and into the TARDIS.

Hartley turned to Martha with a smile. "Don't be surprised if we ever pop in again," she said kindly. "I like to check in on my friends."

Martha hesitated and gave Hartley pause. She stopped, only half inside the TARDIS as she waited for Martha to gather her thoughts. "You've got something really special, here," she finally said, serious and imploring. Hartley was stunned by the force of her stare. "Don't forget that," she finished with an edge, almost as if it were some kind of threat.

Disregarding the hard edge to the words, Hartley simply smiled. "Wouldn't dream of it," she promised, reaching out to squeeze the Martha's shoulder before disappearing back into the TARDIS. The doors shut behind her with a resounding click.

She expected the Doctor to change the subject, maybe suggest something he knew she couldn't refuse – like witnessing the invention of hover-boards, or getting her copy of Alice in Wonderland signed by Lewis Carroll himself – but instead he was muttering to himself under his breath, frowning down at the console even as he dematerialised the box and sent them into the vortex.

She made her footsteps extra loud on the grating as she stomped up towards the console, and it seemed to snap him out of his daze. He looked up at her in surprise, perhaps sensing her irritation. She certainly wasn't doing anything to mask it.

"What?" he asked warily, already on the defensive. He knew exactly why she was upset, and she didn't appreciate him pretending he didn't.

"You weren't even going to tell me you were dropping her home?" she asked, keeping her voice even and measured. She never was one to lose her temper and this was no exception, but she still felt a curl of anger in her gut.

Only, if she really thought about it, it wasn't anger at all but instead a simmering hurt caused by his careless actions.

"I agreed to one extra trip," he reminded her, his voice just as measured. There was still a spark in his eyes that suggested there was more going on inside that enigmatic brain of his than she could reach.

"I thought we were a team," she said quietly, undeniably shy, letting her eyes drop to the floor.

"You didn't even seem to get along that well with Martha, anyway," he argued, but that wasn't the point and he knew it. "What's this about?" he asked when she didn't reply. "Why now? Why Martha?"

Hartley inhaled deeply, feeling her lungs expand in her chest, letting the cool air relax her. Part of her wanted to make up some lie but she knew it was pointless – he wouldn't fall for it. He was far too smart for that, and he meant too much to her for her to consider being dishonest, even about something like this.

"I guess...I'm trying to prove something," she admitted, staring down at her fingertips, idly scratching at the chipped, sparkly blue polish on her nails.

"Prove something?" he echoed. She struggled to decrypt his emotions from his tone alone, but she still refused to look up. She felt like she were baring something to him, a piece of herself she didn't know how to give.

She let the words sit, heavy on her tongue. "Prove that I can do this," she finally answered the unspoken question. The Doctor shifted closer to hear her quiet voice. "That I can move on with life," she swallowed thickly.

She felt a wave of confusion he wasn't quick enough to hide. "Move on from what?"

The name was a painful one, but she couldn't live in fear of that pain forever. "Rose."

The Doctor fell silent and the sudden quiet was filled with a thousand unsaid words, none of which she could even begin to imagine.

"When it's just you and I, that's different," she began to explain, because she felt like he deserved an explanation. "It's normal, easy, even. Adding someone else, I guess a small part of me, even after all this time, still kind of feels like we're somehow cheating on her. On her memory." The Doctor was terrifyingly silent. "I know that life with you is always moving, and evolving, and I'm trying to keep up, I really am," she promised him with sad conviction. "I guess, in a way, Martha is my way of trying."

She paused, considering the worst.

"When I put it like that it makes me sound like I'm using her, doesn't it?" she whispered, dropping her face into her hands. "I'm a bad person," she gave a groan of self-loathing.

The Doctor let out a sound, sort of a sharp exhale of air that she could almost imagine to be a laugh. "Hartley, I don't believe there to be so much as a single bad atom in your entire being," he told her, the lilting sound of his voice so affectionate she might have even described it as tender.

She huffed a laugh of her own, looking up to meet his eyes and finding them glittering warmly. Her smile grew and soon the pair were grinning at one another. Something crackled in the air between them, and she felt the outrageous urge to slip closer and wrap her arms around his middle, press her ear to his chest and listen to the beautiful song of his double heartbeats.

She knew she couldn't – whether for fear of the intimacy or the impending rejection, she couldn't say – but instead she crossed her arms, hugging herself as a poor substitute.

"Go on then," she eventually said, breaking the eye contact and instead looking up at the bobbing of the time rotor, "what's next?"

He didn't say anything for a moment, and the whole time she could feel his stare on the side of her face; until finally he turned back to the console with an overexcited bounce that made her grin.

"Well," he began, stretching the word out into several syllables. "That man on the news did say something rather concerning," he said with a sniff, quickly pumping the lever to his right. "What kind of time travellers would we be if we didn't at least check it out, eh?"

He gave a wide smile, eyes sparkling with warmth, and she knew then that the Doctor's decision to go back had nothing to do with the men on the telly, and everything to do with her wanting to keep ahold of Martha for as long as she could (unhealthy though it may have been).

She barely had time to smile back before the TARDIS was landing with a wheeze and he was bounding down to the doors, throwing them open and sticking his head back out into Martha's flat.

"No, I'm sorry," he said loudly, continuing on as though they'd left mere seconds ago, rather than several long minutes, "did he say he was going to change what it means to be human?"

Martha responded from outside but Hartley couldn't hear it from across the room. Thankfully the Doctor stepped out, Hartley quick to follow, smiling at Martha kindly. Martha looked more than surprised to see them there, having all but given up on ever seeing them again.

"What do you know about the project that lab is working on?" the Doctor was asking her seriously, straight down to business.

"Absolutely nothing," Martha replied, and when the Doctor frowned she hurried to add, "but Tish sent me an invitation in the mail. It says I can bring a plus one."

The Doctor brightened. "Brilliant!"

"Sorry, Hart," Martha said with an apologetic grimace. "It only says I get an extra one..."

The Doctor waved off her words before Hartley could say anything. "She can just use the psychic paper," he told Martha, turning to look at Hartley impishly. "You can be anything you want – celebrity, journalist, visiting royalty..." he trailed off temptingly.

"I think I'll just stick with something unremarkable," she rolled her eyes. "Shareholder sounds innocuous enough."

"Well, the event's not till late," Martha interjected. "What're we meant to do until then?"

The Doctor waved away her concerns. "Oh, you just go about your day as normal, then get ready and we'll meet you back here when it's time to leave," he said with a shrug.

Martha blinked. "What, you're going to jump forwards in time to meet me later because you can't handle waiting an extra few hours?" she asked, incredulous.

Hartley laughed quietly, nudging the Doctor with a roll of her eyes. "He doesn't like staying idle," she told Martha in a stage whisper, and she gave a huffing laugh in reply.

"Yes, yes," the Doctor tutted, "come on then." He turned and led Hartley back towards his ship. "See you later tonight, Martha!" he called over his shoulder. "Or in only five minutes, from our perspective!"

"Wait!" Martha cried, and both travellers turned to raise their eyebrows in surprise at the desperate note to her voice. She was a mess of anxiety, and Hartley frowned in concern as the unpleasant feelings washed over her. "You are coming back, right?" she asked them carefully, hope itching in her heart.

The Doctor was confused by the question, but Hartley understood in the way only someone who wasn't the Doctor could. "Martha, on my brother's life, we'll be back," she vowed. Martha thought for a moment then seemed to accept it, nodding her head and waving as the pair disappeared back inside the TARDIS.

"I don't think swearing on Jack's life is a particularly good standing point," the Doctor said offhandedly as he took them into the vortex where they would have the time to get ready before the gala. Hartley had to admit, it really was handy having a time machine that could pop you forwards a few hours to the start of something. You'd think it would mean they were never late to anything – but unfortunately that wasn't the case.

"Why not?" she asked as she peeled off her cardigan and laid it over the railing.

"He's immortal."

Hartley rolled her eyes. "So am I," she shot back. "Besides, it's the sentiment that counts, Doc." She rolled her neck, then turned and headed for the door that led to the rest of the wonderful, infinite ship. Spinning on her heel, she walked backwards so she could peer at the Doctor as she left. "Wear the tux!"

"But you know that thing's bad luck!" he very nearly whined.

"Wear it anyway!"

"Why?!"

By now she'd stepped around the corner, but too the time to quickly pop her head back into the room, purely to shoot him her most impish grin. "Because you look good in a bow tie."

The Doctor only stared at her, and she laughed brightly before disappearing back into the depths of the TARDIS.

She didn't take that long to get ready. She had a quick shower before wrapping herself in a fluffy robe and wandering her way through the seemingly endless wardrobe, looking for something to suit the occasion.

She knew she should pick something she could move in, something she could run in – but there was a voice inside her head, curiously questioning how long it had been since she'd actually dressed up. With the Doctor, there was little opportunity to go to fancy galas and wear pretty shoes, and despite knowing how easily everything could spiral, she longed for the opportunity to get dolled up in a way she hadn't in years.

So she threw caution to the wind and selected a beautiful pink and black dress, one that fell below her knees but still displayed a decent chunk of cleavage. She plucked a pair of similar shoes from the rows behind her, then wandered back down to her room. Laying the dress on her bed, she took time doing her makeup, rimming her eyes in black, lengthening her lashes and painting on a lovely shade of pink lipstick.

Donning her dress and slipping the gorgeous-but-sizeable heels onto her feet, she turned and peered into her full-length mirror.

She was surprised by how she looked – she'd forgotten what it was like to feel so beautiful. It had been years since she'd bothered with elaborate makeup. But now, looking at herself, she realised that made her sad. She supposed it was just something she'd had to give up for this life – and it was a sacrifice she'd willingly make again.

Resolving to ask the Doctor if they could go somewhere dress-worthy every now and again, Hartley slipped some bangles onto her wrists, turning and clicked her way towards the control room.

"Finally!" the Doctor called before she even stepped into the room. "I was ready ages ago! If we didn't have a time machine, we'd be late for sure!"

She walked towards him but he paid her no attention, hurriedly typing away at the keyboard, eyes focused on the monitor. An amused smile curved at her painted lips. "I was barely even an hour," she corrected him with an exasperated laugh. "You know, for a Time Lord, you really do have a horrible sense of time."

"We aren't accustomed to time being experienced linearly––" he began to say defensively, spinning where he stood to look at her. The rest of his argument seemed to die on his lips.

Bemused, Hartley raised her eyebrows at him, self-consciously running her hands down the layers of tinted, delicate mesh she was wearing.

"I know it's a bit fancy," she said quickly, looking down at herself and wondering if she'd aimed for but hadn't actually hit pretty, rather landing somewhere in the realm of ridiculous. "But we never go somewhere nice like this. I thought that, well, maybe I could try looking properly beautiful for once," she joked wryly, hands twisted together in anxiety.

The Doctor didn't say anything, he continuing to stare at her. It began to make her feel awkward. She couldn't have possibly put a name to the emotions swimming behind his eyes, and she briefly wondered if the magnitude of what he could feel as a Time Lord surpassed human standards – if he felt more deeply than any human ever could. And maybe that was one of the reasons he wouldn't let her feel him – because the weight of it might just crush her into dust.

To cover her the awkwardness she felt, Hartley moved forwards, careful not to let her thin heels slip between the grating. The Doctor watched her carefully as she approached, like she was a bomb he didn't trust not to explode in his face. She met him at the console, reaching up gingerly to straighten his black bow tie.

"I haven't seen this old thing since Pete's world," she said, voice light in an attempt to crack the thick shell of silence that had befallen them. "I always was such a sucker for a bow tie," she added coyly, grinning up at him teasingly from under her lashes.

The Doctor seemed to be chewing on his words. She could see him struggling to decide what to say. Was he going to ask her to change? Tell her kindly she looked just to the left of silly and she should go put on something less fancy? Her insecurities arose, and she tried not to squirm under his heavy gaze.

"We should go," he finally said, and she found herself disappointed by the dismissive remark. He pulled away, turning back to the console and beginning the process of landing them back in Martha's flat. Hartley stepped against the railing, running a hand down her loose, curly hair.

The TARDIS shook beneath them and she gripped the railing, careful not to overbalance in her pretty yet wildly impractical shoes. Maybe it was irresponsible, but sometimes a girl just wanted to wear some pretty heels. Besides, there was no guarantee anything would go wrong enough that she'd need to make a quick get away. With any luck the night would be all cocktail shrimp and champagne.

The TARDIS landed with a muted thud and everything went still. The Doctor said nothing, but he was standing at the console, staring down at it with a pensive frown marring his handsome face.

Hartley gingerly prodded against him with that muscle inside of her that she was only just beginning to understand, but his emotions were sealed up tight, hidden behind a wall she couldn't have gotten past if she had a million years to try.

Looking away and hoping the Doctor hadn't felt her attempt at an intrusion, Hartley headed for the doors.

But long fingers curled around her wrist, pulling her to a stop. She turned to look at him, noting with a curl of interest that they were almost the same height now, thanks to her heels. He had that strange look on his face again, but there was an impassioned glint to his eyes that threatened to take her breath away.

"Just for the record, Hartley, you always look beautiful," he told her simply, full of a conviction that made her heart race, "no matter what you wear."

She stared back at him, trying desperately to form words, but what could possibly compare? It was one of the nicest things he'd ever said to her, and the way he was staring into her eyes left her feeling unbalanced. He was gazing at her like she were one of the supernovas he so loved to watch from afar; like she were something to be admired with a sense of pure, unadulterated wonderment.

She exhaled at the strength of the Doctor's stare, and for the briefest of moments she could have sworn his eyes flickered down to glance at her plump, fairytale-pink lips.

The moment was broken rather abruptly by a sharp rapping at the doors. The Doctor jerked away from her as though he'd been stung, clearing his throat loudly and quickly typing something into the console before bounding down the ramp towards the doors.

"Ready to go?" he asked Martha the moment he could see her. Hartley had to take an extra moment to compose herself, shutting her eyes and willing her pulse to slow down. It was nothing; nothing had happened, it was just her imagination. She needed to focus.

"Don't you look spiffy," Martha's voice was teasing from outside the TARDIS. Hartley heard her footsteps as she stepped inside the ship, ready to head for the event. "You know, we could have just caught a cab," she added wryly.

"But why pay for a cab when we have the TARDIS?" the Doctor sounded genuinely bewildered by the suggestion and Hartley, now recovered, turned to face them with a small laugh that came easier than she expected.

"Wow," Martha said appreciatively, coming to a stop in front of Hartley and letting her eyes roam her dress. "You look lovely," she added, though the slight frown to her face and gleam of negativity in her heart didn't drop.

Without hesitating Hartley dug deeper, if only to find out why Martha looked so miserable all of a sudden. What she found was a sense of inadequacy and a low, simmering jealously.

And that just wouldn't do.

"Me?" Hartley asked, covering her brief glimpse into Martha's heart with a sweet smile. "Have you seen yourself? You look stunning. I lovethis colour, it really suits you," she chattered, the words distracting but at the same time wholly sincere. Martha really did look like a vision.

In the back of her mind she knew she was being somewhat overenthusiastic in an attempt to gloss over her strange blunder with the Doctor, but it worked on multiple levels.

Martha's expression evened out, and her shoulders slumped as she relaxed. Hartley felt a warmth grow in her heart, and she knew she'd successfully moved her out of the negativity and into something that was kinder on herself.

Martha smiled, the expression miles brighter and more sincere than it had been only a moment ago. "You too, Hart," she said kindly. "Where did you get your dress?"

"TARDIS wardrobe," she shrugged. "And who knows where she gets the clothes from?"

Martha looked like she had a hoard of questions, but the Doctor interrupted them with a tut. "You humans, you'd gossip all day about fashion and colours if I let you," he sniffed. "Shall we get going, or would you like to continue talking about the pretty patterns you drape over yourselves because society dictates you must?"

It sounded similar to something the old him – his previous regeneration – had said an eternity ago, back when it was just them and Rose. Hartley was suddenly struck with the reminder that they were the exact same person, just with different exteriors. It was a dizzying thought.

Martha balked at the Doctor's comment. "You really are alien," she murmured.

"More like male," Hartley murmured. Martha snorted out a laugh, and Hartley grinned at her companionably.

The Doctor muttered something about humans that she didn't care to hear, rolling her eyes and moving in the direction of the door.

The TARDIS landed with a violent judder and Martha and Hartley grabbed onto one another in an attempt to stay upright. "Off we go then," the Doctor said, sweeping past them towards the doors. "This Lazarus fellow," he began as they all stepped out into the cool evening air, "what do you know about him?"

It wasn't freezing cold, but being spring it was still a little chilly. Hartley had always liked the cold, however, and enjoyed the goosebumps that broke out over her exposed, pale skin.

"Nothing, really," Martha answered him with a shrug. "Tish hasn't had a chance to tell me anything about her new job, and I never have time to keep up with the news."

"So we're going in blind," Hartley murmured, a sinking feeling in her gut.

The Doctor sighed, reaching down to fuss with his cufflinks. "Oh, black tie," he muttered. "Whenever I wear this, something bad always happens."

"It's not the outfit, that's just you," Martha smirked, and while Hartley had to agree, she couldn't help but think of human brains inside metal men, glinting silver bright in her eyes as they raised their weapons up with the intent to kill; to upgrade. "Anyway, I think it suits you," Martha continued on, oblivious to Hartley's inner turmoil, "in a James Bond kind of way."

"James Bond?" the Doctor echoed dubiously, reaching up then to fuss with the bow tie that Hartley had already fixed. He sounded incredulous, cringing at the comparison, only for the expression to even out into one of hopeful intrigue as he reconsidered it. "Really?"

Hartley giggled, unable to help herself, and Martha joined in. The Doctor looked dangerously close to pouting but he decided not to – probably to try and preserve his dignity – falling silent as they moved towards the doors of the large, towering building.

The words Lazarus Laboratories hung high above them, and Hartley felt a glimmer of foreboding. She was used to it – life with the Doctor was almost never trouble-free, after all. She raised her chin as if silently telling the fates to go screw themselves. She was ready for whatever the universe was going to throw at them. She could handle anything, so long as she had the Doctor at her side.

The Doctor surprised her by holding out an arm when they reached the large staircase leading up to the doors. Taking it with a grateful smile, she allowed him to help keep her balance as they travelled up the stone steps.

The man at the door was scowling, looking very much like he was holder of the worst job in all of space and time. But they were undeterred. Martha was already fishing her invitation from her clutch and the Doctor produced the psychic paper, handing it over to Hartley in a subtle move the man couldn't spot.

"Invitations?" the man asked them tonelessly, a glassy look to his eyes.

Martha held out hers, saying, "this is the Doctor, he's my plus one," and the man barely glanced up at her as he waved them through. Hartley stepped forwards, holding out the psychic paper with her most confident smile.

The man scanned it, frowning for a moment too long before looking up at her, only to do a double take much like a character in an early morning cartoon might. "Hello," he greeted her, looking a whole lot more interested in life now that she was standing in front of him. It was flattering, but also wholly unwelcome.

Uncomfortable, Hartley could only murmur an awkward, "hello."

"You're Ms. Daniels," he said, as though she didn't already know her own name. "You're one of the largest shareholders in the company – I've heard of you."

Hartley doubted this, as it wasn't even true, but she smiled demurely and gave a humble nod of her head.

"Did you bring a plus one?" he asked suddenly, scanning the empty space behind her as though someone might suddenly materialise out of thin air and stake their claim. "A boyfriend, or maybe a partner?"

"Are you meant to ask that?" she frowned uncomfortably.

"Just doing my job," he leered at her in a way that made her skin crawl, and she suddenly wished she wasn't displaying quite so much cleavage.

She was unsure how to proceed. It had been a long time since she'd had any sort of male attention – pretty much as long as she'd been with the Doctor. Even in the past with Jack she'd managed to stay under the local men's radar – though that was mostly because she never left the house and everyone was more infatuated with Jack than her.

There had been one – lovely Henry from the 30s during the time they met Amelia Earhart – but his attention hadn't been unwelcome, and he certainly hadn't been so creepy about it, either.

She was shifting her weight from foot to foot and trying to come up with a clever way to get out of the situation when the Doctor reappeared at her side, winding a long arm around her middle, fingers curling at her waist where the seam of her dress lay.

"Coming, love?" he asked with the utmost ease, and she felt an unexpected thrill at the casual use of the term of endearment. She glanced up at him but he wasn't looking at her. He was staring at the man, a thunderous sort of look to his face, like he was just daring him to say something more.

He backed off instantly, even going so far as to step back and hold out his hands in surrender. He waved them through the doors weakly and the Doctor's hand moved naturally to the small of her back, guiding her through the doors and into the heated air of the building.

Hartley breathed a sigh of relief when the leering man was out of sight. Relaxing into the Doctor, she looked up at him with a smile. He sniffed, guiding her deeper inside the building to where she presumed Martha had already gone. "Thanks, Doc," she said, warm with gratitude.

The Doctor shrugged like it was no big deal, and she could tell he didn't want to linger on the topic, so she changed the subject as they stepped into a larger room full of people in black tie. With just a single glance she counted so many pearls it made her dizzy.

"Do you think the food'll be good?" she asked the Doctor, pressing a hand against her rumbling stomach.

"Smells good enough!" he said, suddenly enthusiastic as he leapt onto a passing waiter carrying a tray of hors d'oeuvres. "Oh, look, they've got nibbles! I love nibbles," he beamed, hand dropping away from her spine to swipe up a handful of food.

Without him touching her she felt like she could finally breathe again, and she watched as he grinned toothily at the waiter before stuffing one of the nibbles into his mouth, licking his fingers clean without any regard for propriety.

Hartley smiled at him fondly and he grinned back around his mouthful of food, making her snort.

"Hey Martha," she greeted their friend, who stood off to the side, scanning the crowd, searching for someone.

"Where were you?" Martha asked curiously. "Did the guy at the door hold you up?"

Hartley nodded her head. "Something like that."

"I guess the psychic paper isn't quite as infallible as advertised," she said to the Doctor teasingly. He ignored her in favour of snatching up another handful of finger food. Hartley rolled her eyes.

"Hello!" a cheerful voice suddenly greeted them. Hartley turned to see a woman the woman from the television earlier – Martha's sister – hugging Martha with a smile.

"Tish," Martha greeted her sister warmly.

"You look great," Tish said with a smile. "So, what do you think? Impressive, isn't it?"

"Very," Martha agreed.

"And two nights out in a row for you. That's dangerously close to a social life," she added teasingly. Hartley smiled at the joke – she could relate. As far as social lives went, it was pretty much just her and the Doctor, clumsily traipsing their way throughout the whole of time and space.

"If I keep this up, I'll end up in all the gossip columns," Martha replied sarcastically.

"You might, actually. You should keep an eye out for photographers. And Mum, she's coming too. Even dragging Leo along with her."

"Leo in black tie? That I must see," Martha was saying, but Tish was abruptly distracted by the pair of travellers to her right, staring at them with a polite if not slightly perfunctory smile. "This is, er, the Doctor," Martha introduced him stiltedly.

"Hello," he greeted Tish, clumsily wiping his hand on his trousers before shaking her hand. Hartley wanted to laugh, but instead settled for smiling, perhaps just a little too wide to be considered appropriate.

"And that's Hartley," Martha added, gesturing to her. Hartley held out a hand to shake, gripping firmly and smiling at Tish widely.

"Lovely to meet you," she said kindly.

"Are they with you?" Tish asked Martha instead of replying. The smile never dropped from her face, a mask of utter professionalism that Hartley had to respect.

"Yeah," Martha nodded quickly.

Tish's smile became tight. "But they're not on the list. How did they get in?"

"The Doctor's my plus one, and Hart got a last minute invite in the mail," Martha lied smoothly, impressing Hartley with her quick response. Still, Tish looked like she had questions but before she could begin to ask them, the Doctor interjected, derailing her thought process.

"So, this Lazarus, he's your boss?" he asked conversationally.

"Professor Lazarus, yes. I'm part of his executive staff," Tish seemed pleased for an opportunity to talk about herself. They could only nod in polite interest, while Martha gave a scoff.

"She's in the PR department," she rolled her eyes in her sister's direction.

"I'm head of the PR department, actually," Tish sniped back defensively.

Martha paused. "You're joking."

"I put this whole thing together."

"So, do you know what the professor's going to be doing tonight?" the Doctor interrupted them again. Hartley hid a smile, she knew how he hated domestics. "That looks like it might be a sonic microfield manipulator," he mused, turning to look at the machine in the middle of the room with a critical eye.

"He's a science geek. I should have known," Tish sounded kind of derisive about it, as if it were somehow a bad thing. Hartley opened her mouth to say something but Tish continued talking, giving her no opportunity. "Got to get back to work now. I'll catch up with you later," she said, smiling tightly once again before weaving her way back through the growing crowd.

The Doctor watched her go, confused. "Science geek?" he asked, bewildered by the unfamiliar term. "What does that mean?"

"That you're obsessively enthusiastic about it," Martha answered dryly.

The Doctor smiled widely, like he'd just been paid a compliment. "Oh, nice," he hummed, grinning after Tish, utterly clueless. Hartley just laughed, shaking her head fondly at his befuddled expression.

A waiter passed with a tray of empty champagne flutes and Hartley wondered how long it'd been since she'd had a real drink. "I might go get a drink," she told them, glancing over her shoulder at the catering table where a row of full flutes stood shimmering in the overhead lights. "Anyone else want one?"

"None for me," said the Doctor with a wave of his hand. His eyes were on the room, scanning the sea of people, searching for anything at all that seemed out of place. She left him to his detective work.

"I'd love one, thanks," Martha said. Hartley nodded, smiling as she headed for the table with the drinks. Someone stopped to talk to her on the way, asking something about the weather and where she got her shoes, and she made light smalltalk for a few moments before politely excusing herself and moving to the table. She picked up two flutes and heading back towards her friends.

They had been joined by two vaguely familiar people – an older woman in a glittering golden dress and a tall man wearing a tuxedo. Something about the way they were all standing just screamed awkwardness, and Hartley sped up, sensing it was her turn to save the Doctor, rather than the other way around.

"Hello," she greeted them brightly, swiftly cutting through the tension with her happy grin and lighthearted energy. She handed one glass off to Martha, who took it with a tiny smile of relief.

"Mum, this is Hartley Daniels," she said after taking a healthy sip of the champagne in her flute, as if drawing strength from the bubbles. "She's a friend of the Doctor's – and mine."

"Lovely to meet you," Hartley said, holding out her hand to shake. The woman took it with a skeptical frown, but Hartley wasn't to be deterred. "My friends call me Hart," she added with a smile so bright the blind could see it. "You're Francine?" The older woman nodded, so Hartley turned to the man with another brilliant grin, one that no such tension could possibly withstand. "And that must make you Leo."

"Yeah," he shook her hand as well, giving a grin. Hartley thought absently that he really was rather attractive. She pulled away and stepped closer to the Doctor. His hand moved up automatically, palm pressing gently once more to the small of her back. Hartley watched as Francine's eyes followed the movement, her heart full of suspicion.

Hartley wasn't sure what it was they'd done to warrant such a reaction, but she wasn't about to ask her to clarify. Not with tensions running so high.

"I heard Tish was the one to organise this whole event," she added conversationally, keeping her tone light and easy. "She did an amazing job, you must be so proud."

And in the end not even Martha's mother wasn't immune to Hartley's charm. She gave a very reluctant smile along with a vague nod just as the lights dimmed and there was the sound of cutlery against glass to gain everybody's attention.

"Ladies and gentlemen, I am Professor Richard Lazarus and tonight I am going to perform a miracle," the older man from the television began to say, and they all turned to see him standing beside the looming device in the centre of the room, a small smile on his weathered lips. "It is, I believe, the most important advance since Rutherford split the atom, the biggest leap since Armstrong stood on the moon," he told them proudly, and Hartley could feel the Doctor tensing from beside her at his brash promises. "Tonight, you will watch and wonder. Tomorrow, you will wake to a world which will be changed forever."

The man, Lazarus, handed off his cane and opened the door to the device, which she realised now to be a sort of chamber. He stepped inside and shut the door after him. Without any fanfare the machine came to life, whirring loudly and flashing bright light in their faces. The columns around the outside were moving, spinning around the chamber so fast they disappeared into mere blurs of colour.

Hartley wasn't scientifically minded. She had no idea what the man could possibly be doing, but when she looked over at the Doctor and saw his horrified expression, she knew that whatever was happening wasn't anything good.

It seemed to go on forever, the roar of sound and the blinding lights, but then a new noise cut over the whir of the machine, this one a ringing alarm that made the Doctor snap into action.

"Something's wrong," he spoke quietly, but Hartley heard him perfectly even over the rest of the noise. "It's overloading." He broke into a run, shouting a rushed, "protect them!" to Hartley over his shoulder.

Taking her job seriously, Hartley angled herself in front of the Jones family, prepared to take the hit should something go wrong. Of course if the whole building exploded there was nothing her pitiful human shield would do, but she could try nevertheless.

There was shouting from the frightened partygoers around her but Hartley stayed where she was, keeping the Jones family safe. Her eyes locked onto the smoking machine, hands balled into small fists. The Doctor was working at the computers down the back of the room, sonic in hand. Unsurprisingly, he was doing something right. The machine whirred to a slow stop, and before it had even completely died down Martha was forcefully pushing her way around Hartley and climbing up onto the raised stage, wrenching the door open with both hands.

Hartley admired her courage – who knew what had happened inside that thing? The fumes could have been toxic for all Martha knew, but she did it anyway, only out of concern for her fellow human being. A newfound respect grew in Hartley for the woman, but all thoughts of praise were wiped from her mind when a figure stumbled from the depths of the chamber.

The crowd gasped as one, their shock so intense it hurt Hartley's teeth with the force of it.

Clenching her jaw in reaction, Hartley was astounded to see it wasn't a decrepit old man hobbling out of the machine, but rather a youthful man with smooth skin and light blond hair. Hartley wanted to believe it wasn't real, because surely he couldn't have de-aged himself. But with one look over at the Doctor's appalled expression she knew it was anything but an illusion.

"Ladies and gentlemen, I am Richard Lazarus," he proclaimed to his audience, who gasped as one, staring at the man in absolute shock, "I am seventy six years old and I am reborn!"

The crowd applauded him wildly, praising his monumental achievement, but Hartley could only stare. What did this mean for the future? The one she'd visited and experienced? What did this mean for the fate of humankind?

The now-young Lazarus waded into the crowd where people where practically tripping over themselves in their excitement to meet him, or get the chance to touch his skin, like he were some kind of messiah. Hartley felt sick to the stomach by it all.

This wasn't something to praise. It was something to abhor.

"It can't be the same guy," Martha was hissing to the Doctor, gaping at the carefree Lazarus in horror. Hartley was relieved that at least one person in the room could see this for what it truly was. "It's impossible. It must be a trick," she said, struggling to believe it.

"Oh, it's not a trick," the Doctor muttered darkly, half distracted as he scrutinised the now forgotten machine that had worked such impossible wonders. "I wish it were."

"What just happened then?" Martha asked confusedly.

The Doctor was quiet for a moment, but when he spoke his voice was hollow with foreboding. "He just changed what it means to be human."

Hartley had seen plenty of wonders in her time since meeting the Doctor, impossible, magical miracles spread throughout the cosmos. But in that time she'd also learned that just because you could do something, it didn't mean you should. Hartley turned to look at Lazarus, finding him talking with an aged woman, a self-satisfied smirk on his waxen face.

He didn't care about the gravity of what he'd just done; he was simply high on success. Hartley couldn't help but think it was all about to go horribly, abysmally wrong.

"We need to speak with him," the Doctor decided suddenly, marching towards the de-aged scientist without stopping to consider whether it was a good idea. Hartley and Martha were left scrambling to catch up. Lazarus was now eagerly stuffing his face with hors d'oeuvres, ravenous with hunger.

"But what are we meant to say?" Martha hissed at the Doctor's retreating figure. But the Time Lord didn't reply.

"Believe me," Hartley told Martha in an undertone as they followed, eyeing the scientist up ahead with caution, "it's best just to let him get it out of his system. You get used to it."

"Used to what?" Martha asked, but by then they'd already reached Lazarus. Hartley watched him stuff food into his mouth like a man who hadn't eaten in weeks. It reminded her of how starved she felt after one her revivals, and she felt uncomfortable at the comparison.

"Energy deficit," the Doctor strolled right up beside Lazarus, hands tucked into his trouser pockets. He looked startlingly casual, giving off an air of intelligence that usually worked to catch the right people's attention. "Always happens with this kind of process," he sniffed knowingly.

Lazarus' eyes narrowed. "You speak as if you see this every day, Mister...?" he trailed off around his mouthful. It wasn't nearly as endearing on him as it had been on the Doctor, Hartley noted with a grimace of disgust.

"Doctor," the Time Lord corrected him primly. "And well, no, not every day, but I have some experience of this kind of transformation."

Lazarus gave a derisive scoff. "That's not possible."

"Using hypersonic sound waves to create a state of resonance. That's inspired," the Doctor hummed.

Lazarus was struck with surprise that faded quickly into suspicion. "You understand the theory, then," he said shortly.

The Doctor's expression grew dark. "Enough to know that you couldn't possibly have allowed for all the variables," he said, voice flat with disapproval that even the most oblivious of humans could have detected.

But Lazarus was unbothered. "No experiment is entirely without risk," he shrugged. Hartley watched as the Doctor's face dropped into something resembling the oncoming clouds of a storm. She shifted her weight, wondering if she would have to step in. The Doctor rarely lost his temper, but something about this adventure seemed to have the alien on edge, more so than usual.

"That thing nearly exploded," the Doctor said darkly. "You might as well have stepped into a blender."

"You're not qualified to comment," came a sudden voice. Hartley glanced down at an older woman she hadn't noticed before, stood to Lazarus' left. She was flabbergasted at the gall of the Doctor, and Hartley got the feeling she was big on propriety. She was glaring at the Doctor with cold, beady little eyes, dislike simmering under her skin.

Hartley felt indignation flare in her gut, this time totally her own. "Actually, if he hadn't stopped the machine it would have exploded, killing every single person in this building," she informed the woman tartly.

There was a flare of interest from Lazarus, but it melted away as he caught sight of the Doctor's glare. "Then I thank you, Doctor," Lazarus said silkily, anything but sincere. "But that's a simple engineering issue. What happened inside the capsule was exactly what was supposed to happen. No more, no less."

"You've no way of knowing that until you've run proper tests," Martha interjected without missing a beat, staring back at the man imploringly.

"Look at me," he countered arrogantly. "You can see what happened. I'm all the proof you need."

Hartley snorted. "You call yourself a scientist?" she asked snidely. Lazarus' eyes narrowed, but he didn't comment, turning away as if she wasn't worth his time.

The unnamed woman at his side, however, sent her a glare that could rival the Doctor's. When she spoke it was in a prim and proper voice, the sound of it grating on Hartley's nerves. "This device will be properly certified before we start to operate commercially," she told them shortly. Hartley might as well have been able to see the dollar signs flashing in her eyes.

"Commercially?" Martha was incredulous. "You're joking. That'll cause chaos."

"Not chaos; change," Lazarus corrected, utterly unemotional. "A chance for humanity to evolve, to improve."

"This isn't about improving," the Doctor's voice was like ice. Hartley began to seriously consider stepping in, derailing the conversation before her friend could get any more worked up. "This is about you and your customers living a little longer," the Doctor spat, the words with disgust.

"Not a little longer, Doctor. A lot longer," Lazarus sneered. "Perhaps indefinitely."

And suddenly Hartley was interested in stopping the coming battle. Instead she wanted to argue the point. Wanted to tell him it was wrong – unnatural; but how hypocritical would that be? A sadness fell over her, a sort of self-hatred that she couldn't control.

Lazarus may have been an idiot, but he was an observant one. He shifted closer as if sensing she was vulnerable, like a shark smelling blood in the water.

"Do you disagree, Ms...?" he trailed off, holding out a hand for her to take.

She didn't want to touch him, like it might make her dirty, but she wasn't going to brush him off so blatantly. She didn't have it in her.

She took his hand, reluctantly allowing him to press a kiss to the back of it. She only just barely kept from grimacing at the hot press of his lips against her skin. She felt a flare of interest and arousal from him as he leered at her, and she tried not to retch at the sensation, shoving forcefully at her empathic abilities, attempting to lock them away before they made her physically sick.

"Ms. Daniels," she told him in a voice layered with distaste and just as hollow as the Doctor's had been. Lazarus didn't seem to take any notice, seeing only what he wanted to see. "And I do disagree, yes," she answered his question without hesitation, chin tilted up defiantly.

"And why is that?" he asked, voice slimy as he kept hold of her hand in a too-tight grip. She was glad she was able to keep her fingers from trembling, giving nothing away.

"Nobody should live forever," she said, the words holding an edge of pain; of personal experience.

Lazarus peered at her, intrigued. "Are you saying that if you were offered the opportunity of immortality, you would not take it, Ms. Daniels?" he asked smugly, as though with this argument he had already won. Why was it always the ones who thought they knew everything that really knew nothing at all?

That familiar self-loathing reared its ugly head in her stomach, and she shifted at the feeling, swallowing thickly. "If I had the choice – no, I wouldn'tchoose to be immortal," she said with the kind of conviction that no other human on the face of the Earth, except Jack, could understand.

She felt the weight of the Doctor's stare on the side of her face, but she kept her eyes locked with Lazarus, hoping beyond hope that just maybe he would listen to the most sincere warning she knew how to give.

"Hm," Lazarus hummed, eyeing her like a hungry dog and for the second time that night a man made her skin crawl with disgust. "You are something," he said in what was surely meant to be a flirtatious voice, but instead it just made her feel like she was in desperate need of a shower.

"Richard," that old woman interjected sharply, roughly pushing by Hartley in an attempt to snatch Lazarus' focus back, "we have things to discuss. Upstairs."

She stormed off with her nose in the air, jealousy prickling at her skin.

"Goodbye, Doctor," Lazarus sneered. "In a few years, you'll look back and laugh at how wrong you were," he assured him blithely before turning to Martha for a handshake. Confused, the young doctor took his hand, only to gape when he instead pressed an open mouthed kiss to the back of it. As he kissed Martha his eyes remained focused on Hartley. She threw up a little in her mouth.

He must have liked something about her sickened expression – perhaps mistaking it for jealousy – because he smirked a final time, then turned and strolled after the old woman like he owned the bloody world.

The trio of travellers stood in silence for a moment, watching him go with varying degrees of perturbation.

"Oh, he's out of his depth," the Doctor eventually muttered, voice low and rumbling, like the foreboding sound of distant thunder before the storm finally hit. "No idea of the damage he might have done."

"So what do we do now?" Martha asked.

"Now?" the Doctor murmured. "Well, this building must be full of laboratories. I say we do our own tests."

Martha paused, seeming to consider something before lifting her hand with a coy little grin. "Lucky I've just collected a DNA sample then, isn't it?" she said sweetly.

The Doctor's grin was contagious, both Martha and Hartley found themselves smiling back. "Oh, Martha Jones, you're a star," he beamed, pressing a hand to both of their backs and leading them deeper into the building. "There's got to be a directory around here somewhere," he said as they slipped out into a hallway off to the side of the room, successfully escaping the notice of the security patrolling the gala.

Off to the far side of the corridor was a wall with a large map hanging on its surface. Hartley spied it first, dragging them over to it with firm hands, glancing over her shoulder to be sure they hadn't been followed by security.

"Second floor," the Doctor exclaimed, pressing a finger to the image room they needed before racing towards the lift without waiting for either of them to catch up. Hartley and Martha gave matching eye rolls as they hurried to follow.

It had been a long time since Hartley had ran in heels, but it was a skill that was sort of like riding a bike; once you knew how, you never forgot.

Thankfully the Doctor had enough patience to hold the doors of the lift for them and they all slipped inside, taking it up to the second floor and stepping out into an empty, sterile corridor that seemed to stretch on for ages.

"This way," the Doctor said, turning left and making his way down the hall.

"How do you know?" Martha asked skeptically.

"Memorised the map," he replied in the ultimate 'duh' tone of voice. She huffed in response but the Doctor paid no mind, pulling out his sonic screwdriver and using it on a door halfway down the corridor. It clicked open and he slipped inside, pocketing the sonic as he strolled up to the computers with all the confidence of a man who belonged there.

The room was filled with several hulking pieces of equipment that Hartley couldn't have even begun to understand the purposes of. Suddenly feeling so intensely out of her depth, Hartley could only pause in the doorway warily before clearing her throat loudly. Martha and the Doctor were both already moving over to the devices and beginning to turn them on with a practised ease that came from years of study and inherent intelligence, but at the sound they turned to look at her.

"I'll stand watch," she said, the only slightly useful thing she could think of to offer.

"You sure?" the Doctor was frowning, pausing his task for a brief moment to look at her.

"Someone's gotta be the muscle in this team," she told him with an attempted grin, falling back on wry humour to try and mask how suddenly inadequate she felt in comparison to the two doctors before her.

"You?" Martha sounded amused, which was actually kind of offensive.

"Stronger than I look," she said simply, which may not have been true. She wasn't very strong, but her training with Jack was enough that she knew how to use an opponents strength against them, and wasn't it basically the same thing? She could protect them – with her life, if it came down to it. Literally. "You guys get started," she ordered, reaching forwards and picking up a wrench that was laying idle on the bench, tossing it in the air and catching it with deft fingers, just glad she hadn't embarrassed herself by dropping it to the floor.

Martha and the Doctor both turned back to the equipment while Hartley remained in the doorway, door half-closed behind her while her head remained out in the hall, looking each way to make sure they weren't caught.

She could hear the other two babbling scientific talk behind her but she tuned them out with ease. Her heels were beginning to hurt, a long-forgotten pain that she hadn't experienced in years. But she welcomed it, like a sense of stereotypical normalcy that she'd forgotten existed.

She could hear the faint sound of music drifting up from the floor below them, some beautiful classical song that was heavy with violin. She hummed along, testing the weight of the wrench in her hand. She wondered what Jack might say if he were there.

Stop moping about not knowing what an atom is made up of; you're better than that. You're smart and capable, and don't you forget it, Pretty Lady.

She could practically hear his voice in her ear and she felt a throb of longing for the man who had become more of a sibling than her own sister had ever been.

"Hart!" the Doctor called from inside the room, and she very nearly dropped the wrench she still held, scrambling to grip it properly before spinning around to peer at him curiously. "We figured it out," he said, abandoning the work station and heading for the door where she still stood.

"What's happening?" she asked quickly, listening to an absent Jack's advice and stopping her moping, focusing on the task at hand.

"Basically, his molecular structure is mutating – it's in a constant state of flux," he explained as he approached.

"And that's bad, yeah?"

"Very," he nodded, and she was glad he didn't seem to be looking down at her for not completely understanding.

She hadn't really thought he would – she was just being paranoid. She did that sometimes, assumed the worst before it could happen, that way she wasn't let down.

"He's...changing," the Doctor continued, oblivious to her inner monologue.

"You mean kind of like your regeneration?" she asked, eyes wide as she wondered what it looked like for the Doctor to change everything he was, and what problems it might create if Lazarus was doing the same thing..

But the Doctor put those fears at rest, replacing them with much, much worse ones. "No, nothing like that," he told her solemnly. "This is much, much more dangerous."

She paused. "For him? Or for everyone around him?"

The Doctor frowned, the weight of it heavy in her chest. "Both."

Martha finally caught up to them, having taken the extra time to erase all their activity from the system. It was smart, Hartley realised, something she wouldn't have thought to do herself.

"This way," the Doctor led them from the room, the door creaking shut behind them. "We need to find him before he mutates completely. Who knows what'll happen then?" He sped up at his own words, and Hartley and Martha hurried to keep up. "His office is this way!" he called, slipping through a door to the left and taking them down another hallway, this one ending in a set of large, oak doors.

"This is his office, all right," Martha muttered as they stepped inside. Hartley still held the wrench in her hand, prepared to use it if necessary. It was a pretty pathetic excuse for a weapon, but also the best she could do under such short notice.

"So where is he?" the Doctor mused, moving further into the room and giving it a once-over. It was large and spacious, with an arrogant sort of minimalist feel. Hartley couldn't see anyone – couldn't feel anyone, either – and she relaxed once it was clear they were alone.

"Don't know. Let's try back at the reception..." Martha suddenly gasped. Hartley snapped back to attention, wrench moving up in preparation for an attack. Only there was no assault. Martha took off, jogging to the other end of the spacious office so she was on the other side of a massive, polished desk. Hartley and the Doctor followed, only for the former to stop short when she realised exactly what it was Martha had found.

It was what looked like a mummified corpse, laying on the ground in a familiar, conservative black dress. It was the woman from earlier, the older one who'd been associated with Lazarus. Martha and the Doctor crouched by her body, assessing it with educated eyes.

Hartley remained standing, staring down at the mummified body in dismay. "Is that Lady Thaw?" Martha asked quickly. Hartley felt a painful stab of guilt – she hadn't even known the woman's name.

"Used to be. Now it's just a shell," the Doctor said, his voice thick with curiosity but not pity. Hartley wondered whether that was a good thing or not. "Had all the life energy drained out – like squeezing the juice out of an orange."

"Lazarus?"

"What else could it be?" Hartley asked, brow so furrowed it began to ache.

"So he's changed already?"

"Not necessarily," the Doctor shook his head. "You saw the DNA. It was fluctuating. The process must demand energy. This might not have been enough."

"So he might do this again?" Martha was horrified, but the Doctor could only hum the possibility. "We have to go," she hissed, clumsily climbing to her feet and hurrying from the room. The Doctor was quick to follow, but Hartley waited a moment longer, sending a silent prayer of mourning to whomever may be listening, on behalf of the now deceased Lady Thaw.

"Hartley!" the Doctor called from the hall and she began to run, catching up to them just in time to step onto the lift, the doors sliding shut after her with a ding.

"What do you think he'll do next?" Martha asked as the lift began its descent to the ground floor.

"If it's life energy he's craving, I think he'll be looking for another victim," said the Doctor thinly.

"And after that one, and the next?" Hartley asked anxiously. "When will he stop?"

"I don't think he ever will," he told her just s the lift dinged again and the three of them spilled out into the party once more. The partygoers sent the three of them strange looks as they all moved through the room, almost tripping over one another in an effort to find Lazarus.

"I can't see him!" Martha shouted to them over the combined hum of chatter and music.

"He can't be far. Keep looking," the Doctor ordered her, spinning in a wide circle.

Hartley began to reach out with that new muscle of hers, searching for the kind of ravenous hunger that only Lazarus would be able to feel.

"Hey, you all right, Martha? I think Mum wants to talk to you," Martha's brother Leo appeared, speaking above the noise and bringing Martha to a stop. Hartley and the Doctor continued to scan the room, paying Martha's family no mind.

An older couple to Hartley's right were staring at her oddly. It took a long moment for her to realise it was because she still held the rather large wrench in her hand, the scuffed metal tool standing out amongst the delicate handbags and champagne flutes everybody else was holding onto.

She attempted a charming smile but the couple turned away with judgemental mutters. Her smile collapsed into a frown as she self-consciously hid the dirty wrench behind her back.

"Have you seen Lazarus anywhere?" Martha was asking her brother.

"Yeah, well, he was getting cosy with Tish a couple of minutes ago," Leo told her around a smirk.

"With Tish?"

"Ah, Doctor," at that moment Francine reappeared, marching up to them like a woman on a mission. She was full of intention, curiosity bubbling in her heart. Hartley glanced at her warily, something in her gut telling her that this wasn't going to lead to anything good.

"Where did they go?" the Doctor snapped at Leo impatiently, no time to speak with anyone's mother.

"Upstairs, I think. Why?" he asked innocently. But the Doctor didn't explain, pushing past the small family. Francine's drink spilled all over herself at his carelessness, and Hartley winced as she – much more delicately than he had – slid around them too.

"Doctor – I'm speaking to you!" Francine hollered after him, absolutely appalled by his lack of manners.

"So sorry about that," Hartley quickly apologised for him, as was becoming something of a custom. The Doctor caused trouble, she followed around after to clean up the mess he left in his wake. She wished she didn't like it as much as she did. "He's a little...distracted," she explained awkwardly.

Francine opened her mouth to say something, perhaps an argument or a scolding, but she never got the chance, cut off as the Doctor call of Hartley's name from his place at the lifts. Hartley winced apologetically, casting the small family a wave even as she leapt into the lift after her alien, letting it take them back up towards the floor that held Lazarus' office.

"Little bit rude," she told the Doctor with a puff as the metal box drew slowly upwards.

"Yeah, manners aren't really at the top of my priority list right now, Hartley," he told her sharply. She rolled her eyes at his attitude, listening to the sound of his shoe as it tapped out an anxious beat on the floor of the lift.

"Is he – is he gonna do to Tish what he did to Lady Thaw?" Martha suddenly asked, anxious and scared, and Hartley blinked in surprise, having almost forgotten she was even in there with them.

The Doctor stared back a moment, considering. "Do you want the truth?" he finally asked, empty of emotion.

Martha swallowed. "Yes."

"Then yes."

Martha looked away, crossing her arms to hide her trembling fingers, but Hartley saw them anyway.

The doors opened and once more the three of them barrelled down the halls of the building towards Lazarus' office. Bursting through the doors, Hartley was ready for a fight, only to come to a sudden stop when they found it once again devoid of life.

"Where are they?" Martha demanded, as though either of them knew.

"Fluctuating DNA will give off an energy signature," the Doctor said, fishing his sonic from his pocket and holding it up to the light as he adjusted the settings. "I might be able to pick it up."

The sonic lit up, the sound of its buzzing echoing throughout the large, empty room. He moved it across, searching for the energy signature he knew would lead them to Lazarus.

"Got him," he said, and Hartley whirled around like the mutated Lazarus might suddenly burst through the wall across from them and attack.

"Where?" Martha asked anxiously. His only answer was to angle the sonic towards the ceiling, face scrunched in consternation. "But this is the top floor," she argued.

"But what's one step higher than the top floor?" Hartley asked, thinking quickly.

"The roof," Martha gasped.

This time she was the one leading them, barrelling towards the emergency exit in the corner, the one they knew, logically, must lead to the stairs. The door thankfully didn't have an alarm wired into it, and they took the stairs two at a time in an effort to reach the roof in time to save their friend's sister from a truly horrible fate.

Before they reached the door the Doctor held out an arm, stopping them both and holding a finger to his lips. Though Martha was reluctant she still obediently followed his orders, making her steps silent and following him out onto the roof, Hartley close behind.

Up on the roof, surrounded by the crisp night air, Hartley was momentarily distracted by the view.

The city stretched out before them, London's lights glowing enchantingly. She wondered suddenly if any of the people in the city were in danger. Should they fail in either curing or stopping Lazarus, would anybody else get hurt? She could help but feel like the responsibility of it rested heavily on their shoulders; as it so often did.

She was pulled from her fleeting distraction by the sound of Lazarus' voice. He was quoting a passage she was intimately familiar with.

"Between the idea and the reality, between the motion and the act-"

"Falls the Shadow," she completed the passage without so much as a blip of hesitation. All eyes flew to her and she flushed under the scrutiny.

"Stunningly beautiful and an Eliot fan," Lazarus leered at her, making Tish bristle from beside him. "Well, aren't you a double threat?"

"Four published books and a Masters in Literature from Cambridge, and here I am, reduced to an 'Eliot fan'," she muttered to the Doctor dryly. He gave a low snort of a laugh.

Lazarus, on the other hand, cocked an eyebrow at her words. She felt him only grow more intrigued by her show of fire, and she wanted to gag when she felt his spike of interest like a palpable thing.

"Martha, what are you doing here?" Tish hissed, glaring daggers with her eyes.

"Tish, get away from him," Martha warned carefully, arms held out as if she could reach across the feet between them and snatch her sister to safety.

Tish scoffed. "What? Don't tell me what to do."

"I wouldn't have thought you had time for poetry, Lazarus, what with you being busy defying the laws of nature and all," the Doctor said dryly. Hartley crossed her arms over the fabric of her dress, her eyes focused on Lazarus, watching his every move. She told herself she'd be ready if he attempted any sort of attack, but she couldn't make the promise aloud.

"You're right, Doctor. One lifetime's been too short for me to do everything I'd like. How much more will I get done in two, or three, or four?" Lazarus mused with a cocky smirk that Hartley found herself desperately wanting to smack off.

"It doesn't work like that. Some people live more in twenty years than others do in eighty," the Doctor argued, gentle and not at all confrontational. Hartley knew that if there was a way to settle this amicably, the Doctor would find it. "It's not the time that matters, it's the person."

"But if it's the right person," Lazars countered, "what a gift that would be."

"Or what a curse. Look at what you've done to yourself."

Lazarus' face dropped into a disdainful frown. "Who are you to judge me?" he asked the Doctor, quivering with barely-suppressed anger. Hartley could feel the way it burned at his nerves, like the flames of a fire burning deep in his body. She feared it might soon consume him entirely.

"Over here, Tish," Martha said, anxiously waving her sister away from Lazarus.

"You have to spoil everything, don't you?" Tish hissed, upset by the interference. "Every time I find someone nice, you have to go and find fault."

"Tish, he's a monster!"

"I know the age thing's a bit freaky, but it works for Catherine Zeta-Jones," Tish argued.

"Tish," Hartley interjected, not usually one to lose her patience, but desperate times. "Turn around." The younger woman blinked in confusion, but then obediently turned around to see what all the others could.

Lazarus was no longer in the form of a human. Instead he'd morphed into a massive kind of skeletal scorpion, like nothing you would ever find on present-day Earth. It lifted its thick neck to reveal the stretched, waxy skin of a human face.

"What's that?" Tish asked weakly, not able to comprehend what she was seeing before her.

"Run!" the Doctor shouted, wasting no time answering Tish's redundant question. Hartley was surprised to feel his hand slip into hers, but relief flooded her at his touch. She was grateful for the extra support, as sprinting away from a giant monster hadn't been what she'd had in mind when she'd picked out her shoes for the evening. The door was only a few metres away and the Doctor yanked her in after them, letting her go to sonic it shut, then hurrying down the stairs after her, taking them two at a time.

The staircase was tricky to navigate at the speed they were travelling. She was sure she was going to twist an ankle, and by the time she'd reached the bottom she'd completely given up.

Pausing in her escape, Hartley reached down to unbuckle her impractical, towering heels. "Don't really have time for a wardrobe change, Hartley," the Doctor called over the roars and bangs of Lazarus trying to get through the locked door separating them.

She ignored him, yanking off her second shoe, staring at them mournfully for a beat and then throwing them at the Doctor purely out of spite. They hit him in the shoulder and then fell to the floor with a thud. The Time Lord grabbed his bruised shoulder, wincing.

"Is now really the time to go barefoot?" he asked with a sniff. "We're not exactly at the beach."

"Do you wanna wear the heels?" she sniped back.

He grimaced at her sass, but they were broken from the familiar banter by another roar, this one seeming to shake the very foundations of the building they stood in. The lights went out, only the low glow of the emergency lighting allowing them to see, and a repetitive alarm blared throughout the entire building.

"What's happening?" Martha asked her sister quickly.

"An intrusion," Tish answered, trembling with fear as she glanced up at the door where Lazarus was still desperately trying to break in. "It triggers a security lockdown. Kills most of the power. Stops the lifts, seals the exits."

"He must be breaking through that door," the Doctor said heavily, baring his teeth in frustration before turning towards the staircase leading back down to the lower levels. "The stairs, come on!" he called over the alarms.

He reached for Hartley's hand again as though it were instinct, and she took it even though she didn't have any shoes slowing her down. She ran with him, the mesh skirts of her dress swirling wildly around her knees

They were barely halfway down the first flight of stairs when there was another great roar and the deafening bang of the roof's door being smashed in. "He's inside!" Martha screamed.

"We haven't got much time!" the Doctor yelled back.

Hartley pushed herself as fast as she could, her bare feet slapping against the cold metal of the stairs, legs aching from the pace. The building was only three floors high, and Hartley was in exceptional shape from their constant stream of adventures. But still, the exercise coupled with the panic had her puffing by the time they reached the ground floor where all the gala's guests were staring around at one another in bewilderment at the sound of the blaring alarm.

"Tish, is there another way out of here?" the Doctor demanded, voice carrying in the large, cavernous room.

"There's an exit in the corner, but it'll be locked now," Tish gasped for breath.

"Martha, setting fifty four. Hurry!" he ordered as he tossed her his sonic, which she managed to just barely catch with the tips of her fingers. "This way," he continued in the same breath, retaking Hartley's hand and dragging her towards the podium along the far wall.

He didn't hesitate to leap up onto the podium, eyes shining with worry.

"Listen to me! You people are in serious danger!" he shouted to the crowd at large. He received only dubious silence in reply. "You need to get out of here right now!" he bellowed gravely.

"Don't be ridiculous," a woman near the front finally sneered. "The biggest danger here is choking on an olive."

From above them there was the sound of smashed glass and then an almighty roar. Finally, chaos overcame the crowd.

People shrieked in terror as they laid eyes on the mutated Lazarus. It reared its head, human face glinting wetly in the lights, and it snarled ferociously. It looked even bigger to Hartley now that it was in a smaller space, and her heart stuttered in her chest.

The Doctor dashed away without pausing to explain why, but Hartley was too focused on getting as many people out of the building as possible to bother finding out why. In the far corner she could see Martha had finally gotten the doors open, and the sea of panicking partygoers were pouring out through them like a thunderous stampede. Some people, however, were frozen in their shock, staring up at the monster in abject horror.

"Go!" Hartley yelled, but her cries were lost over the thing's wild screeches.

She didn't think, she just acted, throwing herself off the podium and racing across the floor. A young waiter was sobbing distraughtly in the corner, and she grabbed him by the shoulders, shaking him fiercely as she pushed him in the direction of the doors.

"Run!" she shouted in his ear. The poor guy gave a terrified cry as one of Lazarus' bony legs got a little too close for comfort, a wave of hot, rot-scented air rushing by their faces. "Go!" she screamed again and with a final shout of fear, he obeyed, fleeing out the doors with the others.

Spinning in a circle, Hartley looked for others to help and found the same woman who had scoffed derisively at the Doctor just moments ago. She was staring up at the monster, mouth agape in her horror.

"No! Get away from her!" the Doctor shouted at the beast, and again Hartley didn't take a moment to think. She was still holding the wrench in her free hand, the metal slick with sweat from her grip, and she figured now was as good of a time to use it as any.

Taking barely a beat to aim she threw it squarely at Lazarus' head. He moved while it was in the air but it still hit him on the chest, dragging his attention away from the woman.

The Doctor took hold of the distraction she'd created, appearing by the terrified woman's side and urging her from the building.

Only problem was, now Lazarus' attention was focused solely on Hartley, who had absolutely no clue what to do next. Death by giant-mutated-scorpion would definitely be a new one – and she could only hope that having the life-energy sucked out of her was something she would actually be able to wake up from. She wasn't in the mood to test her gift's limits now.

"You don't want to do this, Lazarus!" she yelled up at him, scrambling for something, anything to say that might stop his path of destruction and save them all. What would the Doctor do? she asked herself. The answer was, of course: talk. "You don't want to hurt people! You just want to help them! That's all you've ever wanted to do!" she shouted desperately.

The creature – Lazarus – suddenly hesitated, pausing in his vicious attack. She was admittedly shocked that it had worked, but her surprise wore off when he didn't stay idle for long, letting out another thunderous roar and thrusting his barbed tail in her direction.

Letting out a frightened shriek, she ducked it just in time, only barely avoiding a hit to the face.

"Lazarus!" the Doctor's voice distracted him, and the scientist-turned-abomination turned his attention away from a panting Hartley. Instead he focused on the Doctor, finding him glaring up at him with all the force of a raging monsoon. "You don't touch her!" he bellowed, his voice almost as thunderous as the creature's roar.

The force of it surprised Hartley, as well as the wave of protectiveness that swept over her, all of it emanating from the furious Doctor who was too busy saving them all to spare the time to hide his emotions away where she couldn't see.

Lazarus roared at the Time Lord, who realised he now had its full attention, taking quick advantage of the situation. The strange feeling Hartley felt herself caught up in suddenly abated and she whirled around to stare at Lazarus. Her hands balled into fists, prepared to start swinging no matter how pointless it would prove to be against a monster of his size.

"What's the point? You can't control it. The mutation's too strong. Killing those people won't help you!" the Doctor yelled up at it, and much like it had with Hartley it paused, listening to his words.

That surely meant there was some shred of his humanity left. Some part of Lazarus still remained. She let herself latch onto hope.

"You're a fool," the Doctor suddenly shouted, and Hartley started in surprise, staring at the Doctor incredulously. She hadn't expected him to goad the thing – she could only hope he had a plan and wasn't just acting on a whim. "A vain old man who thought he could defy nature. Only Nature got her own back, didn't she? You're a joke, Lazarus! A footnote in the history of failure!" the Doctor snarled.

Abruptly he turned, taking off down the corridor. Lazarus chased after him without a second thought, infuriated by his mocking words. "That was your plan?!" Hartley screamed after him in sheer exasperation. He didn't hear her, just sprinting away with Lazarus nipping at his heels. She'd thought he was trying to reason with it, not lure it away as bait.

Bloody alien.

Like always, all she could do was trust that the Doctor knew what he was doing. She knew what he'd want her to do next, and promptly rushed down to where the Jones family was heading for the stairs. "Hart?!" Martha called but Hartley didn't stop, gripping their arms and pushing them forwards, herding them from the building.

"Go, go, go," she barked, glancing back just to be positive Lazarus was gone.

"But it's gone!" Francine argued.

"Probably not for long," she replied, guiding them hastily down the stairs. She hissed when she felt a sharp pain in her feet, and with a glance down she found it to be glass from a smashed champagne flute. Tears sprang into her eyes but she couldn't stop, she didn't have that luxury. She kept running, biting her lip in an effort to keep from crying out in pain.

The foyer was full of people, and Tish was shouting, "we can't get out. We're trapped!"

Hartley looked over at Martha who still held the sonic in her hand. "There must be an override switch," she said, thinking quickly. "Where's the security desk?"

"There!" Tish pointed and Martha didn't hesitate, throwing herself over the desk and using the sonic on the machinery behind it.

Hartley shifted her weight from foot to foot, trying to keep the pain from growing to be too much to handle. There was little she could do but endure it.

It felt like hours passed but really it was only a few moments. Finally the lights flickered back on, lighting up the entrance, and the doors opened with a click. The panicked crowd streamed out, tripping over themselves in their haste to escape.

Disregarding her pain, she turned to where Martha was climbing back over the desk, straightening her dress and glancing up at Hartley with wide eyes.

"Good job!" Hartley told her as enthusiastically as she could manage through the blinding pain in her feet. Martha hadn't noticed the bloody footprints she was leaving on the carpet, but that was for the best. "Now I've got to go get the Doc," she added, turning to look over her shoulder on the off chance the Doctor might reappear. There was no such luck.

"What about me?!" demanded Martha.

"You should stay with your family," Hartley told her in a rush.

But Martha only scoffed. "Fat chance," she said strongly.

Hartley hesitated, wavering where she stood. She didn't want to put Martha in unnecessary danger, but it seemed like an all-hands-on-deck sort of situation. "Okay," she agreed, shifting her weight to her heels and trying not to let Martha see the pain on her face. "We've gotta go."

But Martha stopped her with a shout. "One moment!" she called, and Hartley turned to look at her impatiently. Martha had turned to her family, all of whom were staring back at her expectantly. "I've got to go back in there with Hartley," she told them apologetically.

"You can't!" her mother exclaimed, horror and terror warring for pride of place in her heart. "You saw what that thing did. It'll kill you," she cried.

"I don't care," Martha replied stubbornly. "I have to go."

"It's that Doctor, isn't it?" Francine demanded, looking over Martha's shoulder to pin Hartley with a suspicious glare. "He and that Hartley woman," she added in a low, disapproving voice, as though Hartley couldn't still hear every word. "That's what's happened to you. That's why you've changed."

"He was buying us time, Martha," Tish said. "Time for you to get out, too."

From somewhere deep within the building there was another hungry roar, and Hartley's heart leapt into her throat. "Martha!" she called urgently. There wasn't any time for this – the Doctor needed them now!

She couldn't see Martha's face, but her mother looked absolutely horrified by whatever it was showing.

"I'm not leaving him," Martha finally said, apologetic but sincere, before turning her back on her family sprinting towards Hartley. Hartley didn't hesitate, leading the way up the fancy staircase even as her feet burned with each step. "Where do you think he is?" Martha yelled as they climbed the stairs, Hartley taking care to avoid the piles of shattered glass. The pain was bad, but she was running on adrenaline so for the time being, it was bearable.

"Follow the noise!" she called back, and that was exactly what they did.

They could hear the foreboding roars of Lazarus as they echoed throughout the building's maze of halls. As one they headed in the general direction of the noise, and were sure they were getting close when there was the massive boom of an explosion.

It shook the entire building, foundation and all. Hartley and Martha immediately changed trajectories without so much as a word to one another. They'd barely cleared one hallway before they barrelled into another body.

Hartley flinched, thinking at first that it may have been Lazarus, but almost immediately she realised the arms around her weren't those of a scorpion-monster, but rather decidedly humanoid, familiar in feeling. Looking up, she sagged with relief when she confirmed it was just the Doctor.

"Ah!" he exclaimed, staring at them both in disbelief. "What are you doing here?"

"Returning this," Martha was positively beaming, and the Doctor removed his arms from where they were wrapped instinctively around Hartley, taking the sonic from Martha with wide eyes. "Thought you might need it."

"How did you...?"

"Heard the explosion; guessed it was you," she grinned. Hartley was just puffing, breathing through the pain in her feet and running her eyes over the Doctor to check he wasn't injured, almost like it were an instinct to do so.

The Doctor nodded his head. "I blasted Lazarus," he told them simply.

"Did you kill him?" Martha asked hopefully.

From behind them there was an ear-splitting crash, the pinging sound of glass hitting the floor. Hartley just about sighed her disappointment, getting the feeling that this whole thing was far, far from being over.

"More sort of annoyed him, I'd say!" the Doctor shouted, grabbing them both by the arm and pushing them down the hall in front of him, hurrying to get them to somewhere they'd be safe.

Hartley was beginning to doubt there was such a place. The mutated Lazarus seemed like he would be able to get to them from anywhere.

Her feet were burning, blood flowing from her wounds, but she didn't complain. Her wound, her pain wasn't important in that moment. What was important was putting a stop to Lazarus once and for all, and getting her rather mortal companions and all the humans out in the street out of imminent danger.

Spilling out into the room where they'd begun the night, they came to an abrupt stop. Broken plates and leftover food was strewn wastefully across the floor. It was like a scene from a horror film; the public place abandoned in a time of disaster.

"What now? We've just gone round in a circle!" Martha cried, spinning on her heel in an effort to spot Lazarus, who they knew couldn't have been far behind.

The Doctor didn't have an answer. His eyes scanned the room, searching desperately for something that would inspire the next phase of his plan.

But as predicted, barely a second passed before the hulking form of Lazarus was crashing through the wall opposite them, clumsy in its desperation to reach them. Hartley opened her mouth to swear but the Doctor interrupted, gripping her by the arm and shoving her in the direction of the large device in the middle of the room – the very one Lazarus had used to destroy himself only a short hour before.

"We can't lead him outside. Come on, get in!" he ordered them over Lazarus' guttural snarls. He wrenched open the door and hastily pushed both women inside before slipping in after them, letting the door slam shut behind him.

It was an incredibly tight fit. Hartley felt not only the Doctor pressed against her entire body, but Martha too, the human's chest heaving with desperate breaths. It was silent for a moment, even the monster outside the machine having gone eerily silent.

It was like the calm before the storm, Hartley realised with a sinking heart. Something terrible was about to follow.

"Are we hiding?" Martha whispered, shifting to try and make herself more comfortable, but there was barely enough room to breathe, let alone get cosy.

"No, he knows we're here," the Doctor murmured back, voice low as he stared at the walls of the machine like he could see through them, eyeing the mutant beyond. "But this is his masterpiece. I'm betting he won't destroy it, not even to get at us."

"But we're trapped!" Martha argued, her volume rising.

"Well, yeah, that's a slight problem," he admitted, not making eye contact.

"You mean you don't have a plan?" she asked critically.

"Yes, the plan was to get inside here," he replied defensively.

"Then what?" Martha cried in frustration. Hartley closed her eyes, focusing on her breathing, trying not to think too much about the burning sensation in the delicate skin of her feet. It was like she were standing on hot coals, imaginary fire licking at her soles.

"Well...then I'd come up with another plan."

"In your own time, then."

The Doctor suddenly snapped into action, struggling to get his arm at the right angle to dig the sonic from his jacket pocket.

"Hey!" Martha snapped when he pressed her even more firmly to the wall.

"Sorry, sorry," he muttered distractedly, paying her little attention. "Here we are," he crowed triumphantly. Hartley opened her eyes in time to catch his pleased grin.

"What're you going to do with that?" Martha hissed in bewilderment. Clearly she didn't yet know exactly how useful the small tool could be. Sonic screwdriver wasn't nearly enough of an accurate description. It was so much more.

The Doctor grinned widely. "Improvise."

With quite a bit of difficulty the Doctor managed to wriggle his way down to the bottom of the cylinder they were trapped in. Hartley knew what was going to happen even before it did, and she closed her eyes in preparation.

"Hart," the Doctor's voice was horrified, and she winced at the sound.

"It's fine," she assured him, glad her voice came out steady and even, unwavering even with the pain she was in.

The Doctor said nothing and she knew he was staring at the smears of crimson she'd left on the pristine white floor of the machine, blood leaking from the wounds in the flesh of her feet.

"Come on, Spacewalker," she prompted him when he didn't move, just stared silently down at the blood she'd left behind, emotions locked tightly away. "Forget about me and save the day already."

She struggled to keep her voice light, but thankfully the Doctor listened anyway. A moment later their small prison was filled with the familiar buzzing of the sonic screwdriver. There was no room for either woman to look down and see what he was doing, but they both had unequivocal faith that whatever he was doing, it was going to save them.

"I still don't understand where that thing came from," Martha apparently liked to talk when she was anxious, something Hartley could identify with. Maybe it was a human trait – babbling when overcome with nerves. "Is it alien?" she asked nervously.

"No, for once it's strictly human in origin," the Doctor said, voice stormy from below them. The hulking shadow of Lazarus' new form could be seen circling the machine, a menacing presence. Hartley felt oddly like she were treading water in the middle of the ocean, circled by a great white shark and knowing the end (or at least one of them) was well on its way.

"Human?" Martha asked incredulously. "How can it be human?"

"Probably from dormant genes in Lazarus's DNA. The energy field in this thing must have reactivated them. And it looks like they're becoming dominant," the Doctor rattled off the information as he worked, barely paying the words he was saying a lick of attention.

"You're saying that's something we could have potentially become?" Hartley asked him, trying very hard not to imagine the entire human race as giant scorpion monsters.

"It was some option that evolution rejected for you millions of years ago, but the potential is still there. Locked away in your genes, forgotten about until Lazarus unlocked it by mistake," he told them quickly, the sonic's buzzing filling the air.

"It's like Pandora's box," Martha gasped.

"Exactly," he confirmed grimly. "Nice shoes, by the way."

Glancing over at Hartley, Martha had never looked more bewildered by life with the Doctor than she did in that moment. She gaped in pure perplexity but Hartley could only lift her shoulders in a weak shrug. She'd either get used to it eventually, or she wouldn't. That much was up to her.

From all around them there was a thrumming sound. The lights of the machine turned on, a bright, blinding blue, and Hartley squinted against its glare. "What the hell is it doing?" Hartley asked the Doctor, a terrible feeling in her gut telling her that she already knew the answer.

"Sounds like he's switched the machine on," he told her as he worked. He sounded offhanded, but she knew it was just an attempt to keep Martha, and probably herself, calm

It didn't work. "And that's not good, is it?" Martha asked nervously.

"Well, I was hoping it was going to take him a little bit longer to work that out," he admitted with a grunt. Hartley felt the strange urge to bash her head repeatedly against the wall of the machine. The thrumming picked up its pace, loud in their ears as the lights grew brighter, burning at their retinas.

Hartley could feel Martha begin to shake from where they were still pressed together. Martha opened her mouth to urge the Doctor on, "I don't want to hurry you, but-"

"I know, I know. Nearly done!" he shouted back.

"Well, what're you doing?"

"I'm trying to set the capsule to reflect energy rather than receive it!"

"Will that kill it?"

"When he transforms, he's three times his size. Cellular triplication. So he's spreading himself thin!" the Doctor yelled back. Hartley couldn't help but notice it wasn't actually an answer.

The sounds around them got louder and Hartley could feel her skin begin to vibrate, the machine humming with energy.

"We're going to end up like him!" Martha cried. Hartley mirrored the feeling, wondering if she, in all of her unique impossibility, would be able to recover from such a transformation. Would she heal from it, or would she be forced to live a life like Lazarus forever?

Either way she'd survive it, but she doubted Martha or the Doctor would be quite as lucky – or unlucky, depending on how you looked at it.

"Just one more..." the Doctor huffed. A beat, then a deafening bang that shook the container they were packed into like sardines. It felt as if the capsule was going to tip over.

But then it didn't, everything falling disconcertingly silent. The Doctor climbed slowly back to his feet and Hartley and Martha both shifted as much as they could to allow him the space to move. He waited an extra moment, ear pressed to the door, before he finally pushed against it. It opened without resistance, but then again, Hartley doubted there had been use for a lock on such a machine.

The room seemed suspiciously empty, no giant mutant waiting with its frothing jaws to attack them on sight. Despite its absence, Hartley felt anything but at ease.

"I thought we were going to go through the blender then," Martha admitted as they stepped further out into the room, staring across at the large, empty space.

"Really shouldn't take that long just to reverse the polarity. I must be a bit out of practice," the Doctor murmured to himself but Hartley had stopped listening, catching sight of the now-human Lazarus laying face down on the floor across the room. Even though every footfall was like walking through a pit of fire, Hartley rushed towards him in concern.

Neither the Doctor nor Martha joined her, but she didn't care, dropping to her knees beside the changed, unclothed man and tentatively pressing her fingertips to his throat, hoping against hope that she might find a pulse.

"Oh, God. He seems so human again," Martha's voice was gentle, kinder to the ears after the deafening roar of the machine they'd just been trapped inside of. "It's kind of pitiful."

There was no pulse, and no thrum of energy in his aura. He was gone.

"Eliot saw that, too," the Doctor's voice was grim, and Hartley sat back on the floor, folds of her dress splayed out around her like the petals of a wilted flower. "This is the way the world ends. Not with a bang, but with a whimper."

"For those who have crossed, with direct eyes, to death's other Kingdom, remember us – if at all – not as lost, violent souls, but only as the hollow men," Hartley added – the best eulogy she could come up with – saddened and grim. She pressed a hand to Lazarus' bare shoulder, his waxen skin cold to the touch, and said a gentle prayer in her head.

None of them even had a chance to say anything before the room was flooded with authorities. Men with guns and paramedics in high-vis vests barrelled into sight, heading for the trio crowded around the dead body, shouting questions as if they could answer.

The Doctor began to speak, pulling his psychic paper from his pocket and holding it up, but his words were lost under the sound of rushing blood in Hartley's ears. The adrenaline was beginning to wear off, dissipating in her blood like water evaporated by the sunshine.

Nobody was paying her any attention, the paramedics swarming the corpse before her like flies to a carcass. She stood to her feet, hobbling across to one of the upturned chairs in the corner. She picked it up with a wince at her protesting muscles, collapsing down onto it with a heavy exhale, exhaustion clawing at her mind.

Her feet were aflame, and she hesitantly picked up her right leg, crossing it over her left and tilting her foot up so she could see the sole.

It was smeared that horrible crimson, as if she'd walked through an entire puddle of her own blood. It was still flowing, the cuts unable to heal with all the glass still embedded inside. The absolute last thing she wanted to do in that moment was dig it all out, but she didn't really have a choice.

It was with a reluctant sigh that she grit her teeth and began to dig her fingernails inside the wounds.

She wanted to cry out in pain, but she was stronger than that. She managed to keep her reaction down to nothing except the faint watering of her eyes, jaw aching from the way she had clenched her teeth.

She didn't know how long she was there, the pain making time difficult to track, but it felt like an eternity before she was approached, and she still hadn't even finished digging all the glass out of her first foot.

The Doctor's wonderful face swam into view and she realised he was crouched before her, staring up into her eyes with a concern he allowed her to feel.

"You might be immortal," he said, strangely stern, like he were berating her for something. "But you still feel pain just as much as any other human, Hart," he reminded her tersely, and her chest twinged.

"Shouldn't have taken my shoes off," she grumbled, chastising herself for the stupid move. "I guess an aching sole isn't as bad as a shredded one," she added wryly, staring down at her work, unable to meet the Doctor's eyes.

His hands moved into her line of sight, coming to rest over hers and forcing her to stop. She froze, finally looking up at him with big, sad eyes.

He sighed, but there was no annoyance or irritation in the sound, no condemnation or anger, but just a sincere concern and a glint of guilt, like it were somehow all his fault in the first place.

"Here," he murmured, reaching into this pocket and pulling out a small pair of tweezers, holding them up with a tiny but genuine grin. "I think this needs a Doctor's touch," he said coyly. He looked mighty proud of the joke and she managed something of a laugh that only disappeared the moment the ends of the tweezers dug into her burning flesh.

He worked much more efficiently than she had, gently pulling out the shards of broken glass that had been embedded inside the delicate skin of her soles.

"Gotta say," he began conversationally, as though they weren't bent over her bleeding feet with a cooling corpse laid not ten feet away, "I'm quite impressed you managed to stay on your feet as long as you did. Most people wouldn't have been able to bear it."

She lifted her shoulders in a weak shrug, trying not to cry out in agony as he yanked free a particularly stubborn shard of glass. "The adrenaline helped," she told him modestly. "Nothing like a massive, mutated monster hell bent on killing your friends to get you running across a glass-covered floor."

"You weren't worried about him killing you?" he asked, eyes on his task and an undertone to his voice that made her curious.

"Nah," she replied, giving another shrug that went unseen. She didn't elaborate, he already knew everything she would have said anyway, so there was no point.

He'd moved on to the next foot, and now that the glass was all gone from her right one, she was beginning to feel her skin tingle as the wounds sealed themselves up, her immortal biology working to heal the damage. It would take awhile before it was completely healed, but the pain began to ebb away significantly.

"Thanks, Doc," she said a while later as he finally put down her foot, using a rag he'd fished from his bottomless pocket to clean off the dried blood coating the bottom of her feet. "You don't happen to have a pair of shoes in those magic pockets of yours, do you?" she asked jovially, tired but feeling a whole lot better now that she was on the mend.

"Fresh out," he clicked his tongue, but his eyes moved to scan the room thoughtfully. "You'll definitely need some to get out of here, though," he said, eyeing the piles of shattered glass that dotted the floor like landmines. "I doubt you'd let me carry you," he added as an afterthought.

"You'd be right," she agreed with a small, sincere smile that she was thrilled to find reciprocated.

"Wait here," he ordered her, standing from his crouched position with a huff and wiping his hands off on his pants, uncaring of the stains he left.

"What?" she blinked in surprise. "Where're you going?"

"Wait here," he repeated, wagging a finger at her sternly. "I mean it, I don't want to come back and find your feet all bloodied up again."

"You have my word," she vowed even as she rolled her eyes, but apparently it was good enough for him because he nodded his head and turned, disappearing around the corner.

She sat quietly for a moment, watching the humans around her. The paramedics were just now loading Lazarus' corpse into a bodybag, a gurney waiting off to the side. Police were taking statements from people around the room as well as snapping photos of the aftermath of all the chaos. She wondered what the point was, but figured they had procedure to follow, regardless of its usefulness.

The Doctor had only been gone about a minute before someone was stepping into her line of sight. She thought it was him, but looked up to find it was actually Martha. Her relatively new friend sighed the sigh of exhaustion before picking up an overturned chair and brushing it off, taking a seat beside the immobile Hartley.

"Been a bit of a wild night," she said lightly, scanning the crowd of serious-looking authorities going about their business with bewildered frowns as they tried to work out exactly what had happened here. Hartley wondered whether the Doctor would ever tell them the truth, or if he'd leave them to figure it out on their own.

"Given your statement?" she asked Martha conversationally.

"Yeah."

"The Doc?"

"No, he flashed that freaky paper of his and said you two were exempt, or whatever," Martha told her with a shrug.

"Sounds about right," she agreed with just a hint of a smile.

One of the paramedics wandered over to them, a smile on his face. He held a blanket in his hands and without asking he threaded it around Hartley's shoulders.

"You looked cold," he explained – which was strange because she wasn't. She was too polite to argue though, smiling at him kindly and pulling the blanket tighter around her shoulders. It was sort of itchy, but she didn't want to complain. "Are you okay?" he asked as he gestured to her feet.

The Doctor had cleaned off most of the blood, but her skin was still stained a faint crimson, the kind that would only wash off with soap and a little time. "I'm fine," she assured him.

"Do you want me to have a look at them for you?" he asked with a suave smile. Hartley cocked an eyebrow in disbelief, wondering if it was possible that this guy was actually hitting on her while in the presence of a dead body.

She opened her mouth to politely decline but before she could a familiar lanky form stepped between them.

"Got your shoes, Harts," the Doctor said in a cheery sort of voice, her heels from earlier that night dangling from his fingers. She found it odd that he'd called her by the nickname, as he'd never done so before. It was always 'Hartley', and on the rare occasion just 'Hart'. She was bewildered by it all, but instead of bringing attention to it she just took the shoes with a grateful smile.

"You went all the way back upstairs to fetch them for me?" she asked in surprise, taking them from him with a smile. They were heavy in her hands but she liked the weight, glad she'd have something to protect her from the glass covering the floor like a blanket of deadly snow.

"Of course I did," he said in the sort of tone that made it seem like he was offended by her surprise.

She could do no more than smile as him, reaching down to very gingerly thread the delicate shoes back onto her sore feet.

"Can I help you?" the Doctor's asked the paramedic who had yet to move from his spot. She looked up to see the young paramedic's face flush red. He seemed to have lost his previous confidence, muttering an excuse and scurrying away. The Doctor huffed, murmuring something under his breath that sounded an awful lot like, "three times in one night...never wear that blasted dress again..."

She turned her head away to hide her bemused, if not slightly amused, smile.

"We should go," Martha said, standing to her feet and dusting off the skirt of her dress.

"Right you are," the Doctor agreed. Hartley took his proffered hand, allowing him to gently help her to her feet. His skin was cool and dry against hers, but it was just distracting enough to keep her mind from drifting to her aching feet, her healing soles protesting against the heels beneath them.

She was surprised when, rather than let go, the Doctor kept hold of her hand, leading her through the room and thoughtfully navigating her around the piles of shattered glass across the floor. They moved down the stairs in silence, and while Hartley found it was comfortable between her and the Doctor, she could tell Martha had something weighing heavily on her mind.

She decided not to ask, sensing it wasn't the right time. She would come to them with whatever it was when she was ready; pushing her sooner than that wasn't wise. The night air was cool and she tugged the blanket tighter around her, suddenly glad she hadn't left it inside despite its itchiness.

"She's here!" Tish's voice called over the hum of activity out on the street. "Oh, she's all right!" she cried, rushing towards her sister and pulling her into a tight hug. Hartley felt a throb of longing for her own sister and the relationship they'd never had.

The Doctor let go of Hartley's hand in favour of tugging at his bow tie. She eyed him appreciatively once more – she really did love a man in a good bow tie.

"Ah, Mrs. Jones," the Doctor said cheerfully as the matriarch of Martha's family approached, "we still haven't finished our chat."

She wasn't smiling back however. Rather there was a furious look on her face and a righteous anger in her heart, as though he'd done something to personally offend her.

Despite this, none of them could have predicted that she'd slap him clean across the face. The noise it made was loud and seemed to ring out through the night air. The very sound of it made Hartley sick. She gasped in shock, shifting between the two out of sheer instinct, just on the off chance she tried for round two.

Her presence hardly seemed to worry the older woman, however. Francine was on a some kind of misguided warpath. Hartley watched her warily, feeling her dislike and resentment simmering beneath the surface, the force of it making her feel unbalanced.

"Keep away from my daughter," she snarled at him, the words a poorly-hidden threat. Her beady eyes flickered down to glare at Hartley as well. Hartley could only stare back in pure shock. "Both of you," she hissed hotly.

"Mum, what are you doing?" Martha demanded, drawing the attention of the nearby crowd.

"All of the mothers, every time," the Doctor muttered to Hartley but she couldn't find the humour in it, not in that moment, instead staring at Francine in utter bewilderment. They'd barely spoken two words to one another – how could they have done anything to offend her in that time? If anything, the Doctor had saved everyone! Didn't that earn him at least some sliver of respect?

"They're dangerous," Francine told her daughter in a desperate undertone, begging her to understand. "I've been told things."

"What are you talking about?" Martha asked sharply.

"Look around you," the woman gripped her daughter's shoulders tightly, staring down at her imploringly. "Nothing but death and destruction," she said.

The words had more of an impact on Hartley than she could have expected. It cut to her core, made her question whether the irate woman was right.

Everywhere they went trouble followed them like a plague, and with it came death. Was it their fault? Were they somehow cursed? Was there more they could do to stop it, keep it from happening, from spreading like a disease in their wake?

"This isn't their fault. The Doctor saved us, all of us!" Martha argued with a steadfast loyalty that honestly surprised Hartley.

She blinked, taking in the unwavering certainty in Martha's eyes, and the echo of it in her heart. She believed in them – or perhaps it was just the Doctor that Martha trusted, and she were just included in the package.

"And it was Tish who invited everyone to this thing in the first place. I'd say technically, it's her fault," Leo said in a brave attempt to lighten the mood. Hartley pulled herself away from her tornado of thoughts to smile at him in quiet gratitude.

A loud crash echoed from down the street, the sound sharp and shocking in the night air. Hartley's heart froze as she and the Doctor turned as one to stare at the end of the road. She had a horrible, sinking feeling that she knew exactly what the cause of it was, and it was all she could do to hope that she was wrong.

"Stay here," the Doctor ordered her without thought before taking off at a sprint.

"Fat chance," Hartley muttered, shifting her weight from foot to foot to test the pain levels in her soles before throwing caution to the wind and sprinting after him. Her high heels made her feet ache but she didn't have the luxury of time to let them heal up. The blanket that had been wrapped around her shoulders pooled on the ground but she didn't give it a moment's thought. She just ran.

The ambulance hadn't gotten far, barely reaching the end of the road before it had come to a sudden stop. As Hartley approached, she found the doors to be wide open, two lifeless husks laying motionless in the back, drained of their life energy.

The Doctor cast her a glance but didn't comment on her reappearance – probably because it was so predictable – merely pulling the sonic screwdriver from his pocket and holding it to the skeletal remains in the vehicle.

"Lazarus, back from the dead," he said grimly. "Should have known, really."

"This is bad," she muttered.

The Doctor nodded. "You can say that again."

The sound of heels hitting the asphalt met their ears and both of them turned to see Martha and Tish hurrying towards them, staring at the empty ambulance with horror written across their faces. "Where's he gone?" Martha demanded as they came to a stop, scanning the immediate area as if waiting for Lazarus to leap out from behind the industrial bins nearby to finish them off.

The sonic screwdriver beeped, and the Doctor held it up for them to see, quickly following the sound in a circle until finally he was facing the old cathedral that stood behind them, large and towering in the night. The Doctor's expression became shadowed, and a seed of dread appeared in Hartley's gut.

"That way. The church," he told them, voice hard as he began to understand how truly grave the situation was.

Hartley knew now, just as well as he, that they had to do everything they could to end Lazarus themselves or he wouldn't ever, ever stop killing. This was what he was now; hungry for human life. There was no undoing it.

"Cathedral," Tish corrected him suddenly, and they all turned to look at her. "It's Southwark Cathedral. He told me," she said quietly, and the Doctor's expression grew even more grim. He said nothing as he led the way around the side of the looming building, his sonic held out like a weapon, which Hartley knew, under the worst kind of circumstances, it very well could be.

The cathedral was dark and empty, the silence so full Hartley thought she might choke on it. The atmosphere was tense, all of them unsure what they might find inside.

"Do you think he's in here?" Martha whispered anxiously. They all scanned the large open space, pews lined up in cold rows all leading up to a shining, religious alter.

"Where would you go if you were looking for sanctuary?" the Doctor mused, and Martha's face dropped into a thoughtful frown, considering the question seriously.

The Doctor led them up the nave, moving until they finally reached the alter. The temperature seemed to drop the closer they got to it. Hartley knew it had nothing to do with Christ or demons, but rather everything to do with the mutated man now crouching before it.

Lazarus was curled on the hard floor, shivering violently, wrapped in a coarse blanket like the one she'd had wrapped around her earlier. He glanced up at them as they approached, a look of vague acceptance in his eyes, a sadness that echoed throughout the cathedral like an audible sound.

"I came here before, a lifetime ago," the man said, low and defeated. "I thought I was going to die then. In fact, I was sure of it. I sat here, just a child, the sound of planes and bombs outside."

Hartley wasn't sure she understood what he was talking about, but the Doctor didn't have the same problem. "The Blitz," he said evenly, and suddenly her insides coiled, remembering a large, charming smile that felt so much like home and a sea of innocent humans converted into gas-mask zombies.

Lazarus looked up at the Doctor, considering him for a long moment. "You've read about it," he finally said, low and dismissive.

"I was there," the Doctor disagreed. He turned to glance at Hartley, a glimmer of remembrance in his eyes, and she wondered it he was seeing what she was seeing. "We were there," he corrected himself.

She suddenly thought fondly for a moment of an alien with big ears and an oversized leather jacket, all Northern accent and dry humour and such an apparent dislike for her that she'd developed a complex which still hadn't completely faded away.

"You're too young," Lazarus didn't believe him, scoffing in disbelief.

The sound brought Hartley back to the present, and she turned to find the Doctor very nearly smiling. "So are you," he said wryly.

Lazarus laughed, but with it came a sickening cracking noise. Abruptly his chuckles broke instead into gasps of agony as his body contorted with pain.

The Doctor began to walk around him, keeping his eyes trained on the shaking man, but Hartley stood with Martha and Tish, refusing to move from where she had planted herself in between them and the mutated man, a human shield.

"In the morning, the fires had died, and I was still alive," Lazarus gasped as he recovered, skin covered in a light sheen of sweat. "I swore I'd never face death like that again. So defenceless...I would arm myself, fight back, defeat it."

She caught the Doctor's eyes while Lazarus was distracted, watching as he meaningfully glanced up towards the ceiling. Hartley followed his line of sight, seeing nothing but the towering space of the bell tower above them. She didn't understand what he was trying to tell her, but before she could find a way to ask, she grew distracted by Lazarus' loud gasps of pain.

"That's what you were trying to do today?" the Doctor asked him, continuing on with the conversation as easily as breathing. His mind worked so quickly, it was no surprise he was able to multitask so efficiently.

"That's what I did today," Lazarus snapped back, self-righteous indignation flooding his mutating heart. Hartley cringed at the bitter flavour of it.

"What about the other people who died?" the Doctor quickly began to lose his patience, growling at Lazarus in anger, thinking of the innocent lives lost tonight in this man's blind blind, heedless hunt for immortality.

Hartley wished the man would listen, because she more so than anyone else in the galaxy was qualified to tell him what a pointless hunt it was. But you sometimes people wouldn't listen to what they didn't want to hear. Sometimes it was pointless to even try, but that didn't mean she was going to stop.

"They were nothing," Lazarus replied blithely, lip curled back in an animalistic snarl. "I changed the course of history."

"Any of them might have done too," the Doctor countered, voice like venom. "You think history's only made with equations? Facing death is part of being human. You can't change that," he calmed himself down, staring at Lazarus imploringly, begging him to understand.

This was the moment, the one where he offered him a chance, an opportunity to get out before anybody else got hurt. This was him extending a hand, and Hartley wished she could believe Lazarus was going to take it.

"No, Doctor. Avoiding death, that's being human," he spat, like the man before him was disgusting, like he was wrong. Hartley knew better than most that the Doctor was rarely ever wrong. "It's our strongest impulse, to cling to life with every fibre of being. I'm only doing what everyone before me has tried to do. I've simply been more...successful-" he cut off with a loud cry of pain, bones cracking under invisible pressure, the sound echoing around them in the acoustics of the cathedral. Hartley grimaced, watching on with a growing despair.

She could feel his desperation, his righteousness. He truly believed what he had done was for good, convinced he was in the right. But Hartley also felt the undercurrent of fear running beneath his sanctimonious shell. Despite his confident, self-righteous exterior, this man was terrified. But he'd die before he admitted it. Such was the folly of man.

"Look at yourself," the Doctor said darkly. "You're mutating! You've no control over it. You call that a success?"

"I call it progress," Lazarus argued sanctimoniously, the words spat around another grunt of pain. "I'm more now than I was. More than just an ordinary human."

Hartley glanced over at the Doctor, noting the way his lips were tipped upwards, passion in his deep, chocolate eyes. "There's no such thing as an ordinary human," he told Lazarus with conviction, but it went unheard as the mutated man collapsed again, convulsing violently.

Hartley stepped forwards, moving to comfort him in whatever way she could. No matter how vile and misguided the man was, she couldn't just watch him suffer without doing anything about it. The Doctor held out a hand, forearm pressed gently against her abdomen, stopping her from reaching him. He didn't look at her, but she understood the movement for what it was. He was trying to protect her, and her chest twinged with the weight of this knowledge.

"He's going to change again, any minute," Martha whispered to them from where she was stood beside her wide-eyed sister, staring at the writhing Lazarus in abject horror.

"I know," he replied under his breath. "If I can get him up into the bell tower somehow, I've an idea that might work."

Hartley suddenly understood what he'd been trying to tell her before, and she felt dense for not realising it sooner. "Up there?" Martha confirmed, staring upwards with a frown.

But they couldn't talk any more, aware of Lazarus' attention focused back on them with a guttural snarl in their direction. The Doctor moved his arm from where it had been blocking Hartley, stepping away to continue circling the panting, sweating man, staring down at him gravely.

"You're so sentimental, Doctor," Lazarus sneered at him with a series of heaving pants. "Maybe you are older than you look."

"I'm old enough to know that a longer life isn't always a better one. In the end, you just get tired," he told the man with a conviction that hit Hartley like a dagger.

She winced, because the thought of that being her future was a horrifying one. It terrified her, to the point where she sometimes felt like she couldn't breathe. But she knew this wasn't the time to focus on herself and her impending eternity, so she focused back on Lazarus, watching him watch the Doctor, nails biting into her palms in her anxiety.

"Tired of the struggle, tired of losing everyone that matters to you, tired of watching everything turn to dust. If you live long enough, Lazarus, the only certainty left is that you'll end up alone."

There was a pregnant pause. "That's a price worth paying," Lazarus finally said, and when Hartley looked over into the Doctor's eyes, she found them to be hollowed out with an ancient pain she could barely even begin to understand.

"Is it?" he countered darkly.

Lazarus contorted in pain, beginning to change into that thing once more. Hartley cringed at the crack his spine gave, like it was snapping into two beneath his pallid, leathery skin. "I will feed soon," he told the Doctor menacingly.

"I'm not going to let that happen."

"You've not been able to stop me so far," Lazarus said with an ugly sneer.

"Leave him, Lazarus!" Martha exclaimed suddenly from beside her, and Hartley whirled around with a gasp, having been caught up watching the Doctor that she hadn't even realised her friend had moved. "He's old and bitter. I thought you had a taste for fresher meat," she said, attempting to sound enticing, but really just sounding scared.

"Martha, no!" the Doctor warned, but it was too late.

Lazarus lunged, mouth open in a furious snarl as he attempted to reach Martha. Their young friend turned and ran, sprinting for the stairs leading to the bell tower. With a muffled curse, Hartley raced after her, keeping up with ease, even in her towering heels.

"Doctor! The tower!" Martha bellowed back to the Time Lord, but Hartley didn't have the time to turn and look, shoving her way through the door then waving Martha and Tish up ahead of her. At least if she was at the back of the group she'd be the one most likely to take the hit.

Their heels clacked against the stone as they raced up the rickety old staircase as fast as they possibly could. Hartley really hoped the Doctor had a proper plan, because if there was one thing she knew about monsters, it was that you should never, under any circumstances, trap yourself in a bell tower with one.

From below them, the sounds of snapping bones and furious, hungry snarls drifted upwards, and the girls in front of her came to an abrupt stop.

"Did you hear that?" Tish asked in a frightened voice, sounding much younger than she really was, like a little girl asking her sister if the boogeyman really was hidden in her closet.

"He's changed again," Martha whispered back, just as nervously.

"Don't stop moving," Hartley instructed them, pushing gently at their sides to get them moving again. "We need to keep going. Lead him to the top."

They didn't wait any longer, obeying the older woman's order and beginning to run, holding onto the walls to steady themselves in their impractical heels as they climbed higher and higher.

They were just passing a row of windows when the Doctor's voice bellowed, "Hartley!"

Racing towards the openings in the stone, Hartley stuck her head out into the open air, peering down at the Doctor, who stared up at them from the ground with a desperate, anxious expression.

"Take him to the top. The very top of the bell tower, do you hear me?!" he yelled at them when he was sure they were listening.

"Up to the top!" Martha confirmed.

"Guys," Tish grabbed at them in a panic, and Hartley glanced back to see Lazarus barrelling towards them. He was now completely transformed, snarling as his scorpion-like tail thrashed about behind him, knocking into the old walls of the cathedral, bricks raining down like deadly confetti.

Hartley shoved Martha forwards, making sure both sisters were ahead of her as they ran. The next flight of stairs was a tight squeeze, thin and narrow, but they went up single file, moving as fast as they could. It all passed in a bit of a blur of identical corridors and aching feet, but finally they were tripping out onto the top level of the bell tower, nothing but a rickety old wooden rail separating them from certain death.

"Get over there!" Hartley shouted at them, already herding them towards the opposite side of the circular landing, where they would be the furthest from the hungry, infuriated Lazarus.

"But there's nowhere to go!" Tish argued with a hysterical cry. "We're trapped!"

"This is where he said to bring him," Martha shouted back over Lazarus' violent snarls, which were growing louder the closer he got.

"All right, so then we're not trapped. We're bait," Tish spat.

But Tish didn't understand how this worked. She wasn't used to life with the Doctor, the risks it forced you to take every day – but there wasn't time to educate her. Hartley pressed both sisters behind her as Lazarus' skeletal pincers appeared first in the doorway.

"He knows what he's doing!" Martha insisted, referring to the Doctor so many metres down below them, fuelled by their faith. "We have to trust him!"

"Ladies..." Lazarus had finally appeared, bursting through the small door and swiping his scorpion tail at them threateningly. They had to duck to avoid it, and Hartley felt the wind brush her hair as it passed over her head.

"Both of you, whatever happens to me, stay out of reach!" Hartley yelled the two sisters. Martha was fighting to get out from behind her but she remained firm, forcing them to stay where she could protect them. "Stay safe! Promise me!"

"Hart-" Martha tried to argue, stubborn as they came.

"I'm serious, Martha!" she shouted back over Lazarus' growing, hungry roars. "Stay safe!"

From below them there was a sudden surge of deafening noise. Hartley couldn't place it, to her ears it was nothing but a roar of inexplicable sound. She didn't have time to wonder further, focused on ducking under Lazarus' powerful, barbed tail.

Protecting both sisters at once wasn't easy. She took her eyes off Martha for one moment, pushing Tish out of the way of danger, and when she looked back Martha was hanging on for dear life, gripping the edge of the wooden landing as she screamed in terror, legs dangling into empty air.

"Martha!" Tish wailed, reaching for her sister only to be yanked back by Hartley who knew she'd be too close to Lazarus, within reach of his deadly grip. "Hold on!" she shouted, struggling to find a way to get to her sister. "Get away from her!" she screamed at the monster, who only hissed back.

The strange humming sound in her ears only grew louder, and Martha gave a cry of terror, doing her best to hold tight. Staring down at her friend, Hartley suddenly knew exactly what she had to do.

She turned to Tish whose eyes were wide in dread as she thought her sister might die. "When it happens, get to Martha!" she screamed over the loud roar of noise, the unbearable volume making her ears ache and her head throb.

"When what happens?!" Tish shouted back in confusion, panic clouding her eyes. But there wasn't time to explain.

Whirling around, Hartley didn't hesitate. She just threw herself onto Lazarus who immediately turned his attention from Martha to her. Aiming for his eyes, it was all she could do to attack him, distracting him from her floundering friend.

That horrible noise was growing, her head felt like it might explode, and she knew she wasn't doing anything against Lazarus – she might as well have been a fly he was trying to swat away, an annoyance but not a necessarily problem.

She wondered if she'd failed, if they were all about to die or have their life energy drained, but before she could find out Lazarus gave a loud screech and began to fall sideways.

Everything seemed to slow down and she had the time to realise exactly what was happening. They were falling through the centre of the tower, nothing below them but fifty metres of empty air, the end a floor of solid stone. She'd never died from a fall before – she wondered whether it would hurt, or whether it would be quick and painless.

She felt rather at peace at first, like it didn't matter, like it wasn't a big deal. But the more she fell, the more panicked she became. She wished it would go quicker, but everything was so slow, and in her mind she had to deal with the knowledge that the pain was going to come, then beyond it, that encompassing, suffocating darkness, where nothing and no one existed – not even her.

She watched as the landing grew further and further away while she dropped. That loud, unidentifiable sound finally stopped being so deafening, and as she fell she realised it was music.

It was rather beautiful, really, like it was lulling her to her sleep. She couldn't manage a smile as she approached her death, only a tear fell from her burning eyes, but that didn't matter when she finally hit the unforgiving stone with a loud crunch, a wave of agonising pain, followed by absolutely nothing.

---

Until she snapped back to life, her respiratory system rebooting with a painful, violent gasp. Hands were on her shoulders, holding her still even as she fought to sit up. A voice was in her ear, familiar and soothing, but it still took another minute to finally make sense of the words being said.

"...you're okay, Hartley. Hart, you're all right..."

It was the Doctor, and the knowledge of this caused the panic to evaporate from her system. Her eyes rolled around in her head, searching listlessly before she eventually locked onto the sight of him.

He was leaning over her, expression simultaneously concerned and dark. She relaxed further, the sight of him like a balm to her adrenaline-flooded system.

Inhaling shakily, she coughed to clear her dusty airways, blinking her dry eyes and cringing at the metallic taste of blood in her mouth. Her head was aching more than it ever had before, and her back was throbbing, making her realise something must have happened to her spine when she'd hit the ground.

The memory of falling to her death made her shudder. She swallowed around the lump in her throat, looking back to the Doctor who slowly began to lift her up into a sitting position.

"You're okay..." he continued to coo, but it felt more like he was really reassuring himself.

"How long?" she coughed again, bringing a hand to her throbbing head.

"Over ten minutes," he told her, grave and disturbed. Hartley grimaced at the thought of laying there, nothing but an empty shell, for that long. If their positions had been reversed, she wasn't sure she'd have been able to cope.

"Hartley," said a broken voice, and with a blink she gingerly leaned around the Doctor to see Martha and Tish kneeling behind him, gaping at her with tears shining in their similar eyes.

"Told you I was immortal," she told Martha, aiming for humorous, but the horrified look on her face made it clear that the attempt was not appreciated.

She glanced over to her right, taking in the sight of Lazarus laid there, completely bare and without question dead. Her gut twisted in dismay. She slumped against the Doctor, suddenly overcome with exhaustion.

"Can we go home?" she asked him in a small voice, pulling back to glance up into his eyes, which looked more haunted than she could remember seeing even in the months after Rose, all that time ago.

He nodded, not meeting her gaze as he wordlessly scooped her up, one arm beneath her legs and the other behind her back as he lifted her from the cracked, dusty floor. He stood still for a moment, cradling her almost tenderly against his chest, and she allowed herself a brief second to revel in the soothing sense of connection after such a fleeting eternity of feelingless nothing.

"But she was dead! She fell.I saw it," Tish was hissing from behind them. Martha answered her in a matching hiss but the Doctor paid neither any attention, simply holding Hartley closer and beginning to walk. The gentle rocking of his strides made her want to sleep, but the fear of succumbing to the darkness again so soon kept her awake.

She occupied herself by pressing her ear against his chest, listening to the soothing thrumming of his twin hearts and sighing in contentment.

The sisters joined them on their walk back towards Lazarus Laboratories. Tish had questions, and the Doctor answered them, at first in clipped tones, but the longer they walked the more relaxed he became.

His grip on Hartley never once faltered.

Tish asked things about who they were and how they could do what they could do, but he didn't answer those questions, stonewalling her and changing the subject as they approached the building. The closer they got the better Hartley began to feel, her body healing itself more with every pump of her heart.

"You can put me down now," she told the Doctor before they hit the barricades keeping the public away from the building. He hesitated, clutching her closer for the briefest of moments before reluctantly putting her down on her feet.

He kept one arm wrapped around her middle and she welcomed it, glad for his unyielding presence beside her. It made her feel safe, even in this dangerous world of theirs.

Martha and Tish's mother spotted them, scowling at the pair of travellers even as she desperately waved her daughters over. "We'll meet you back at your flat," the Doctor said to Martha who looked like she desperately wanted to argue.

"I don't think your mum'll let you leave right now," Hartley told her soothingly, her voice still croaky and rough. Martha understood, nodding her head as she cast her mum a grimace. "We promise we'll be there," Hartley added, understanding the fear she couldn't help but feel.

They could disappear without saying goodbye. They wouldn't, but all of them held the knowledge that they could.

Martha nodded, hesitating a moment longer before pulling Hartley into a tight hug, clutching her firmly. The grip was painful to her still-sore body but she didn't complain, squeezing back warmly. "You sacrificed yourself for me," Martha whispered in her ear, and Hartley smiled into her shoulder.

"And I'd do it again in a heartbeat," she said, running her hand soothingly up and down her back. She pulled away, feeling Francine's eyes drilling a hole into the back of her head. "Go on, go placate your mum," she said with a smile that was only a little bit forced. "We'll see you back at your flat later."

Martha nodded, turning to stare at the Doctor with a hint of longing that only Hartley seemed to notice, before swallowing and joining the rest of her family.

The Doctor reclaimed his place beside her, hand splayed on the small of her back. He gently angled her towards the road that led to where they'd parked the TARDIS. That seemed like an entire lifetime ago now, she mused, reminded of just how much could happen in so short a time.

They walked at first in silence, the Doctor still firmly beside her, refusing to move as if worried she would collapse on the spot if he so much as stopped touching her. She smiled fondly at his concern, bringing her hands up at rub at her cold arms.

Without so much as a word the Doctor shed his coat and draped it over her shoulders, making her smile despite the way her muscles still ached with every movement. "We're making a habit out of this," she said playfully even as she tugged at the lapels of the tuxedo jacket, pulling it more securely around her. It was warm and his scent wafted around her, comforting in a way she couldn't quite explain.

"Well maybe if you stopped forgetting to bring a jacket every time we leave the TARDIS..." he sniffed indignantly, but there was a hint of a smile playing on his lips that made her laugh.

His smile grew at the sound and she beamed back, heels clicking against the concrete as they strolled in the direction of where they'd parked their home.

"What's your secret?" he asked her suddenly, the smile of wonderment remaining on his lips as he glanced to the side, looking down at her in the orange glow of the overhead streetlights.

"My secret?" she asked, smile faltering in her confusion.

"To happiness," he elaborated, hands shoved into his pockets as he walked, not watching where he was going but rather staring at her like she were the ultimate riddle. She'd been on the receiving end of the same look from him countless times before, but never had it made her smile so. "You're always cheerful, always happy and bright. Even when you're not smiling you shine with light," he said quietly. "After everything that's happened tonight, everything you've been through – how are you smiling right now?" he asked, genuinely perplexed.

She considered the question, glancing up at the sky, disappointed when the lights of London kept her from seeing the full beauty of the stars. "Sometimes happiness is a feeling," she finally answered him evenly, looking away from the starless sky and back at the Doctor, silently acknowledging that his eyes were a sight she'd much rather spend time staring at. "But not always," she said gently, "sometimes, it's just a decision."

She smiled again and looked away from him, back at their path. In the distance she could see the TARDIS, shining blue under the glow of a streetlight, and she felt a wave of content settle over her soul at the sight of it.

"Who said that?" he asked curiously, a warm, unidentifiable note to his voice.

She grinned, glancing back up at him. "Me," she said rather simply, smiling sweetly and turning back to face the approaching TARDIS.

Her hand was swinging idly by her side and she was stunned when the Doctor's crept into hers, intertwining their fingers like it was something they did every day. She looked up at him in surprise and although he wasn't looking at her, there was a smile on his lips that told her he felt just as content as she did. Hartley was overcome with a sincere happiness that was less about decisions and more about genuine feeling. And she loved it.

The TARDIS welcomed them home with a warm, familiar hum in the back of their minds, and they kept their fingers linked even as they moved towards the console, pausing before going any further.

"Maybe I should check you over in the infirmary-" the Doctor began to say, already stepping in the direction of the door to the rest of the infinite ship.

"We both know I'm fine," she said with a roll of her eyes, catching him by their joined hands and pulling him to a stop. "Come on, let's go meet Martha," she added even as she made no move to disentangle their hands.

"Are you sure?" he asked warily. "You don't want to rest, or, or..."

"I'm completely and utterly fine," she repeated, squeezing his hand to emphasise her point. "Back to normal. Guess it took awhile longer because of how...violent it was," she said, stumbling somewhat over the ugly word, forcefully keeping her mind away from the weightless sensation of falling and the feeling of her whole body cracking against unforgiving stone––

"If you're sure," the Doctor said as he squeezed her hand in return, his thumb brushing over the back of it in a soothing rhythm, and she jolted back to the moment with a blink. The simple action had made her heart race and her skin prickle with awareness.

"Positive," she assured him with her most convincing smile.

He finally let go of her hand so he could pilot the ship. She felt a keen sense of loss once they were no longer connected, intertwining her own fingers in an attempt to gain back the feeling of safety he'd provided.

With only a few theatrical twists they were back in Martha's flat, having travelled forwards a few hours to make sure she'd be home. By happy coincidence as they stepped from the blue box and into Martha's living room, the medical student herself was just shutting the front door after her, kicking off her heels and shrugging off her shawl.

"Told you we'd meet you," Hartley told her with a soft smile, leaning back against the TARDIS, also enjoying the softness of the carpet against her feet – which, by now, were totally healed, though still stained red with her own blood.

She'd kicked off her heels in the console room, relieved to have the blasted things off her feet. It had seemed like a good idea at the beginning of the night, wearing such impractical, towering heels. She'd wanted to glam up for the evening, but now she knew it just wasn't something that was possible in their kind of lifestyle. It was an acceptable price to pay, though, for the wonders she saw.

"Were you gone long?" Martha asked curiously as she padded towards them.

"Gone long?" the Doctor repeated innocently.

"Don't give me that," she scolded him lightly. "You've got a time machine. You could have been gone a week for all I know."

Hartley smiled at her quick mind. "We came straight here," she promised, holding a hand over her heart. "Time traveller's honour."

Martha grinned, the expression genuine but also tired, something Hartley understood. She might have been back to complete health, but she was exhausted – not to mention starving. But that would be solved soon enough, either they'd eat in the TARDIS or she'd get the Doctor to take them somewhere fantastic for food; she was craving pancakes.

"Something else that just kind of escalated, then," the Doctor said to Martha, leaning back against the blue box beside Hartley, who smiled at the chaos that was their lives.

"I can see a pattern developing," Martha replied coyly. "You should take more care in the future. And the past. And whatever other time period you two find yourselves in," she added with a chuckle that Hartley couldn't help but echo.

The Doctor grinned too, the expression bright and mischievous. "It's been fun, though, hasn't it?" he asked with a brilliant gleam to his warm eyes.

"Yeah," she agreed, cocking her head and meeting Hartley's eyes, who smiled along with them.

There was a beat, then the Doctor asked eagerly, "so, what do you say, one more trip?"

Hartley smiled, wide and confident Martha would agree, but to her surprise the woman considered it carefully before sighing and shaking her head in the negative. "No. Sorry."

"What do you mean? I thought you liked it," the Doctor muttered in sheer bewilderment, as though her answer simply just didn't compute.

"I do, but I can't go on like this. One more trip," she quoted him sternly. "It's not fair."

"What're you talking about?"

"I don't want to be just a passenger anymore. Someone you take along for a treat. If that's how you still see me, I'd rather stay here," she muttered, and Hartley could see how hard it was for her to say it. Turning down the Doctor's offer, putting her boundaries in place, it took a lot of strength – a strength that some people just didn't have. She was impressive, Hartley had to admit.

She also considered what Martha was saying, and had to admit that she hadn't thought of it in that way. She'd have felt the same, in her position. Having the title of Companion was such a powerful thing, and it wasn't fair to dangle it in front of her as they had been, like a piece of meat held above a dog's head, too high for them to reach. It was almost cruel. Guilt bubbled in her stomach, and she frowned at herself, angry that she hadn't seen it sooner.

She turned to look at the Doctor, who had at the same time looked down at her. Their eyes met and one of the silent conversations that they'd begun to experience drifted in the air between them.

The Doctor was asking questions with his eyes. Was this what she wanted? Was it the right thing to do?

Hartley responded with nothing but a small, gentle smile, and it was all the answer he needed to make the decision for himself. She was just glad to have been included, smiling again, wider as they turned back to Martha.

"Okay, then. If that's what you want," he said, but even Hartley had to admit, the solemn tone to his voice was misleading.

"Right," Martha snapped, hurt by his apparent brush off. "But we've already said goodbye once today. It's probably best if you both just go," she said tightly, turning away from them sharply, probably so they wouldn't see the pain in her eyes.

It did no good for Hartley, who felt it like a punch to the kidney.

The Doctor didn't move, standing there stoically, and Hartley had to roll her eyes. He was absolutely brilliant, beyond anything even imaginable, but he could still be so cluelessly alien.

She let out a laugh, the sound bright and loud in the otherwise silent flat, and Martha turned back to face them with a deep frown. "What?" she asked, looking on the verge of taking offence, as though Hartley was laughing at her.

"He said okay," she told Martha with a smile.

"Sorry?"

Hartley huffed, elbowing the Time Lord in the gut as a prompt. He flinched away from the assault, but she didn't look up to take in his expression, continuing to grin at a confused Martha. "Okay," he repeated, and she felt him nod his head towards the TARDIS.

Martha's eyes flickered between them and the blue box before she broke out into a wide, ecstatic smile, rushing towards them in sheer exuberance. She leapt into the Doctor's arms and he caught her with a grunt of surprise before chuckling as he squeezed her back. A moment passed and he placed her back on her feet.

"Oh, thank you, thank you!" Martha cried happily, throwing herself around Hartley too. Now that she was healed the embrace was easier to handle, and Hartley laughed as she hugged her, squeezing tightly.

They finally let go, and Martha smiled at them both in happiness. The Doctor nudged open the TARDIS door, waving for them to head in. "Well, you were never really just a passenger, were you, Martha Jones?" he asked, and the girl grinned again before all but leaping inside the ship, absolutely without regard for the life that would await her at home while she gallivanted across the stars.

But Hartley had done the exact same thing, once upon a time, so who was she to judge?

She grinned, looking up at the Doctor happily before slipping in after Martha, the ship humming in her mind with joy. Team TARDIS 2.0 – next stop: everywhere.

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A/N: Coming up next: Charlie Chaplin Dreamin'