The ride in the Tardis was as wild and bumpy as usual with Stella and Martha hanging on as tight as possible laughing the whole way as the Doctor ran around the console pulling on this and pushing that. The Tardis landed with the usual jolt sending them to the ground, and the Doctor put on the hand brake.

"There we go. Perfect landing." The Doctor said with a weak smile. "Which isn't easy in such a tight spot."

"You should be used to tight spots by now." Martha commented as she and Stella stood up. "Where are we?"

"The end of the line." The Doctor said. "No place like it."

Martha smiled in excitement as she and Stella ran to the doors. Stella glanced back at the Doctor and was confused by the sad look on his face. She watched as he walked down to them his eyes downcast.

"Doctor, are you ok?" Stella asked gently placing a hand on his shoulder.

"I'm fine." He replied with a tight smile taking her hand in his with a squeeze before they joined Martha outside the Tardis.

"Where are we?" Stella asked as she looked around the room she found herself in.

"Home." Martha replied. "You took me home?"

"In fact, the morning after we left, so you've only been gone about twelve hours." The Doctor said as he looked around. "No time at all, really."

"But all the stuff we've done. Shakespeare, New New York, old New York?" Martha questioned.

"Yep, all in one night, relatively speaking. Everything should be just as it was. Books, CDs, laundry." The Doctor said as he picked up a piece from the laundry horse. Martha quickly grabbed it from him in embarrassment. "So, back were you were, as promised."

"This is it?" Martha asked sadly as she looked over to Stella who had tears in her eyes her heart dropping into her stomach. She should have known that this was all too good to be true.

"Yeah, I should probably er… I should get Stella home and well…" The Doctor said.

"Home? Doctor I'm a wonderer, I have no set home." Stella shook her head with a sigh. "Just drop me off wherever and I'll make my way from there."

"You could stick around here if you wanted." Martha offered making Stella smile.

"She can't, the chances of being seen by someone who will come to know me or her are too dangerous." The Doctor said as Stella roll her eyes.

"He's right unfortunately." Stella shot him a look, but he was refusing to look at her. "But I'll tell you what, the Doctor will drop me off in the future in a place where I can get my vortex fixed then I'll come visit you."

"Sounds great." Martha said with a smile just before her phone rang and the answering machine starts up.

"Hi, I'm out. Leave a message." The answering machine said.

"I'm sorry." Martha said apologizing for the interruption.

"Martha, are you there? Pick it up, will you?" Francine, Martha's mom said over the phone.

"It's Mum. It'll wait." Martha said.

"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." Francine said. Martha grabs the remote and turns on the television, which was on standby.

'The details are top secret…" Lazurus began.

"How could Tish end up on the news?" Martha questioned. Tish was standing next to an elderly man who is making an announcement.

"Tonight, I will demonstrate a device which will redefine our world." Lazurus said.

"What does she do?" Stella asked looking at the TV.

"She's got a new job." Martha said. "PR for some research lab."

"With the push of a single button, I will change what it means to be human." Lazurus said to the reporters before him and Stella felt the lightbulb turn on.

"Professor! Professor!" The Reporters clambered. Martha puts the TV back on standby.

"Sorry. You were saying we should?" Martha said setting the remote back down.

"Yes, yes, we should…" The Doctor said retreating to the Tardis. "One trip is what I said."

"Yeah. I suppose things just kind of escalated." Martha said with a sad smile.

"Mmm. Seems to happen to me a lot." The Doctor commented.

"Thank you. For everything." Martha said to him.

"It was my pleasure." The Doctor said.

"I'll see you soon." Stella said as they hugged.

"See you soon." Martha replied tightening her hug before they released. "Good luck."

"You as well." Stella said before she followed the Doctor back into the Tardis, and it dematerializes. Stella sat in the captain's chair watching as the Doctor worked the controls. "You really don't want to know how he's going to change the definition of humanity." Stella said off handedly. "How could he possibly do that?"

Almost the moment she had heard Lazarus talking a sly plan had formed in her head. The Doctor looked up at her and knew that she was playing him, but the curiosity was just too much.

"You're good." He said as he worked the controls again.

"I know." Stella replied with a smirk.

"But after we find out then that's it." He said pointing at her as he ran by.

"We'll see." Stella said in a sing song voice as the Tardis materializes again in Martha's room. The Doctor ran to the door and stuck his head out.

"No, I'm sorry. Did he say he was going to change what it means to be human?" The Doctor asked a surprised Martha.

-0-

Stella jammed her hands into her pockets hunching her shoulders as she followed the Doctor through the Tardis leaving Martha to get ready. She had a spot of trouble and was hesitant to ask the Doctor, but what choice did she really have.

"This thing is formal, right?" Stella questioned.

"Yep." The Doctor popped his 'p'.

"I don't have anything to wear to a formal event, I only packed stuff for traveling." Stella said looking down at her long sleeved purple shirt, jeans, and black boots that she had put on after her shower. "And something tells me they won't let me in dressed like this no matter what your psychic paper says."

"Oh I'm sure we can find you something." The Doctor said opening a door and leading her into a room filled with racks and racks of clothing.

"Oh, wow." Stella said as she craned her head looking up at everything.

"Go ahead and see if you find anything you like, I have to go see where I left my tux." The Doctor said as he went off in one direction.

Stella wasted no time in beginning to shift through the different clothes items from all over the universe and different time periods. She looked through a ton of different dresses of every design ever conceived, but none of them struck her. Just when she was about to settle when the rack she was looking though shifted, the clothes parting to reveal a beautiful dress on a mannequin behind it.

"Oh it's beautiful, thank you." Stella breathed out and felt a warm hum in reply.

"You ready yet?" The Doctor called out as she took off her clothes.

"Not yet." Stella replied taking the dress of the mannequin. "Can't rush perfection."

"I'm not rushing perfection, I'm rushing you." The Doctor replied with a large smile as he finished pulling on his tux.

"Hah hah, very funny." Stella said rolling her eyes as she tossed a random ballet flat over the rack almost hitting the Doctor.

"Well hurry it up; I'll wait outside with Martha for you." The Doctor said as Stella pulled on the dress which fit like a glove in all the right places.

"Ok, try not to miss me too much." Stella replied and heard the Doctor leave with a laugh. After the dress was on flashing lights from the Tardis lead her over to a vanity table where makeup and accessories had been laid out for her use. "Tardis, you have great taste."

-0-

"Where's Stella?" Martha asked as the Doctor stepped out.

"She'll be along in a minute." The Doctor replied. "You look nice."

"Really, thanks." Martha said beaming at the compliment.

"No problem." The Doctor said then knocked on the Tardis door. "Come on Stella, don't have all night."

"I'm coming, hold your Crystilian Cloppers." Stella replied as she opened the door and stepped out. The Doctor felt his jaw drop of its own accord at the sight of her.

Stella wore a blue green shimmer deep V neck backless ruched banded pencil zipper dress and a pair of strappy ankle high silver heels. Her jewelry consisted of her ring to allow her to appear fully human, teardrop silver hoop earrings, a long teardrop sapphire crystal pendant that hung from silver chain, and a simple silver bracelet with sapphire chips the Tardis had laid out for her. She had curled her hair leaving it loose, applied a light silver dusting of eye shadow to her eyes with blue green accents, a few strokes of black mascara, some black eye liner, and her lips were painted a soft pink

"So how do I look?" Stella asked spinning around with a large smile as she twirled.

"Beautiful." The Doctor breathed out making Stella blush.

"You look pretty handsome yourself." Stella replied with a flirty smile.

"What are Crystilian Cloppers?" Martha asked snapping them out of their flirt mode.

"Oh..Uh…they're like horses, but made of organic crystal." He replied.

"They are beautiful when you watch them run just as the sun is setting. They cast off different color like a rainbow prism." Stella said with a wistful smile.

"That sounds amazing." Martha said.

"We should go there…oh right, last trip never mind." Stella said with a pout looking to the Doctor who rolled his eyes at her.

"Well we better get going this thing starts in a bit." Martha said with a smile at Stella's blatant attempts to get the Doctor to change his mind as the Doctor fiddled with his suit.

"Oh, black tie." The Doctor said as they walked down the street. "Whenever I wear this, something bad always happens."

"It's not the outfit, that's just you." Martha said with a smile. "Anyway, I think it suits you, in a James Bond kind of way."

"James Bond?" The Doctor scoffed then looked pleased at the compliment as they walked up to the building. "Really?"

"And bang goes the ego." Stella joked bumping him with her shoulder.

"Jealous." The Doctor replied bumping her back as the smiled at each other.

"Please, if you're James Bond then I'm the Black Widow." Stella smirked.

Martha watched them with slightly jealous eyes. Stella and the Doctor just seemed to get along so easily and their friendly flirting was driving her crazy. She liked the Doctor a lot to, but whenever she tried to hint at it he would always brush her off. Not in a mean way, but it still hurt none the less especially when he never brushed Stella off and what was worse was that neither of them seemed to realize where they were headed.

-0-

In the middle of the room is a circular dais and on it was a man-sized frosted glass chamber and four upright posts, slightly curved at the top to aim at the chamber. The room was filled with the best of the best all dressed up in beautiful gowns and expensive tuxes as waiters weave through them one passing them with a tray of food.

"Oh, look, they've got nibbles! I love nibbles." The Doctor said happily as he scooped some off the trey handing a few to Stella.

"Nice." Stella said as she popped a few into her mouth.

"Hello." Tish said as she walked up to them through the crowd.

"Tish." Martha said as she hugged her.

"You look great." Tish said hugging her back then stepping back. "So, what do you think? Impressive, isn't it?"

"Very." Martha said looking around the room.

"And two nights out in a row for you. That's dangerously close to a social life." Tish praised.

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

"You might, actually." Tish teased.

"Oh, it's not so bad, in a week more or less they forget you and move onto the next victim." Stella said trying to nab a few more treats from the Doctor, but he held them just out of her reach with a smirk. She poked him in the side causing him to jerk and drop a few which she caught and popped into her mouth with a triumphant smile.

"You should keep an eye out for photographers. And Mum, she's coming too, even dragging Leo along with her." Tish warned her.

"Leo in black tie? That I must see." Martha said looking around then noticed the pointed look Tish was sending to the Doctor and Stella. "This is, er, the Doctor and Stella."

"Hello." The Doctor said with a wave.

"Nice to meet you." Stella added with a smile.

"You as well." Tish replied then looked to the Doctor then back to Martha. "Is he with you?"

"Yeah." Martha answered with a smile.

"Third wheel then?" Tish said looking to Stella sympathetically.

"Not for long if I'm any good." Stella said winking at a passing man who smiled back until he saw the Doctor glaring at him from behind Stella and hurried off much to her confusion. "I think I might be a bit rusty though, Jack would be so ashamed."

"Actually I'm here with both of them." The Doctor said taking Stella's hand in his making her blush. She wouldn't lie and say she wasn't attracted to the Doctor, but the signals he was sending were confusing to say the least, one minute it's the trips over then the next he's being all possessive, it was nuts.

"But they're not on the list. How did they get in?" Tish asked breaking Stella out of her thoughts.

"They're my plus two." Martha said trying to sound convincing.

"So, this Lazarus, he's your boss?" The Doctor asked cutting in before Tish could ask more questions.

"Professor Lazarus, yes." Tish answered then smiled proudly. "I'm part of his executive staff."

"She's in the PR department." Martha said.

"I'm head of the PR department, actually." Tish corrected her.

"You're joking." Martha said surprised.

"I put this whole thing together." Tish said gesturing around them.

"Really? Good job." Stella commented as she looked around her eyes focusing on the machine. It was almost automatic with her in the presence of technology to instantly start to take it apart in her mind and what she was seeing was slightly troubling to say the least.

"So do you know what the professor's going to be doing tonight?" The Doctor asked. "That looks like it might be a sonic microfield manipulator."

"He's a science geek. I should have known." Tish said with a laugh. "Got to get back to work now. I'll catch up with you later."

"Science geek? What does that mean?" The Doctor asked confused.

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

"Oh, nice." The Doctor said smiling at what he perceived as a compliment.

"Your father's caused me enough heartache already with his menopause and his trophy girlfriend." Francine grumbled as she walked into the party.

"Yeah, Mum, I know. It's just something he said last night." Leo said obviously annoyed at the topic.

"Martha." Francine said upon spotting her.

"Mum!" Martha gives her mother a big hug.

"All right, what's the occasion?" Francine asked in confusion.

"What do you mean? I'm just pleased to see you, that's all." Martha said quickly stepping back.

"You saw me last night." Francine said.

"I know. I just miss you. You're looking good, Leo." Martha said looking to her brother.

"Yeah. If anyone asks me to fetch them a drink, I'll swing for him." Leo joked with a mock glare.

"You disappeared last night." Francine said.

"I just went home." Martha answered.

"On your own?" Francine asked looking to the Doctor and Stella, but it was obvious that she was mostly looking to the Doctor.

"This is a friend of mine." Martha said introducing them. "The Doctor and my other friend Stella."

"Doctor what?" Francine asked still looking untrusting, but Stella could care less at the moment, that machine was really bothering her. There was something wrong about it.

"Stella, are you ok?" The Doctor asked quietly following her gaze as the conversation around them was tuned out.

"That machine, it's wrong, not quite sure how yet." Stella answered.

"No, it's just the Doctor." Martha answered. "We've been doing some work together."

"You all right, mate?" Leo asked looking to the distracted Doctor and Stella.

"You're on." Stella nudged him returning his attention to the others.

"It's lovely to meet you, Mrs. Jones. Heard a lot about you." The Doctor said quickly.

"Have you? What have you heard, then?" Francine asked, not at all convinced.

"Oh, you know, that you're Martha's mother and…" The Doctor trailed off. "Er, no, actually, that's about it. We haven't had much time to chat. You know, been busy."

"Busy? Doing what, exactly?" Francine asked with an edge to her voice.

"Oh you know. Stuff." The Doctor said with a shrug.

"We're coming up with new ways to minimize the wait time in the waiting room of the hospitals thus getting the minor cases out faster so we can get to the larger emergencies faster plus giving them more attention." Stella said with a smile.

"And how are you associated with them?" Francine asked eyeing the young girl.

"I work as the head receptionist at the hospital and the Doctor and Martha were helping me decipher between bigger and smaller emergencies." Stella answered easily. "You have a very bright daughter; I see an important future ahead of her."

"Yes, we are all proud of her." Francine said with a smile then opened her mouth to say more, but Professor Lazarus taps on his glass for attention before she can speak.

"Nice, good job." The Doctor said whispered as the crowd quieted down.

"I know." Stella grinned.

"And so humble." The Doctor mumbled.

"Just as humble as you are." Stella countered before Lazarus started speaking preventing the Doctor from coming up with a retort.

"Ladies and gentlemen, I am Professor Richard Lazarus and tonight I am going to perform a miracle." Lazarus began his speech. "It is, I believe, the most important advance since Rutherford split the atom, the biggest leap since Armstrong stood on the moon. Tonight, you will watch and wonder. Tomorrow, you will wake to a world which will be changed forever.

Lazarus went inside the chamber and a pair of female scientists started up the machine pressing a big red button. The four columns started to oscillate and rotate around the chamber as they poured energy into it. Then an alarm sounded blaringly loud.

"Something's wrong." The Doctor said.

"It's overloading." Stella replied and the computer agreed. There were sparks from the controls, then smoke. The Doctor rushed over and got out his sonic screwdriver followed by Stella who started to work the controls directly.

"Somebody stop them. Get them away from those controls!" Lady Thaw ordered.

"If this thing goes up, it'll take the whole building with it. Is that what you want?" The Doctor snapped. "We need to pull the plug."

"Doctor, you're a genius." Stella said as she ran over and pulled out a big power cable causing the contraption to slow down, then stop. Martha rushes to the chamber. "Get it open!"

Martha opened the door, and a young man staggered out much to Lady Thaws delight and the astonishment of everyone else.

"Ladies and gentlemen, I am Richard Lazarus. I am seventy six years old and I am reborn!" Lazarus said and room erupted in wild applause.

"He did it. He actually did it." Lady Thaw cheered clapping her hands. Stella and the Doctor shared uneasy looks as they watched Lazarus descend into the awed crowd posing for the photographers.

"It can't be the same guy. It's impossible. It must be a trick." Martha said as they watched Lazarus mingle.

"Oh, it's not a trick. I wish it were." The Doctor replied.

"What just happened then?" Martha asked.

"He just changed what it means to be human." Stella replied crossing her arms.

"Excuse me." Thaw said as she made her way through the crowd to Lazarus. "That was the most astonishing thing I've ever seen. Look at you."

"This is only the beginning. We're not just making history, we're shaping the future, too." Lazarus said a wild gleam in his eyes.

"Think of the money we'll make. People will sell their souls to be transformed like that." Lady Thaw said greedily. "And I'll be first in line." Suddenly Lazarus stiffened and gasped, then grabbed a tray from a passing waiter and proceeds to eat all the food on it. "Richard."

"I'm famished." Lazarus said as the Doctor Stella and Martha approached.

"Energy deficit." The Doctor said.

"Always happens with this kind of process." Stella added nabbing a nibble from Lazarus's trey and popping it into her mouth.

"You speak as if you see this every day…?" Lazarus trailed off expecting their names.

"Doctor and my companion Stella Quinn." The Doctor supplied. "And well, no, not every day, but I have some experience of this kind of transformation."

"That's not possible." Lazarus argued.

"Using hypersonic sound waves to create a state of resonance." The Doctor said easily. "That's inspired."

"You understand the theory, then." Lazarus said impressed

"Enough to know that you couldn't possibly have allowed for all the variables." The Doctor replied.

"No experiment is entirely without risk." Lazarus replied uncaringly.

"That thing nearly exploded." Stella snapped. "You might as well have stepped into a blender."

"You're not qualified to comment." Thaw snapped back.

"If we hadn't stopped it, it would have exploded." The Doctor shot back.

"Then I thank you, Doctor, Miss Quinn." Lazarus said tightly. "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 said.

"Look at me. You can see what happened. I'm all the proof you need." Lazarus said with a confident smile.

"One supposed success does not mean it will turn out that way every time." Stella ground out. "You could have been a fluke or you're just not experiencing the side effects yet."

"This device will be properly certified before we start to operate commercially." Thaw said brushing Stella off.

"Commercially? You are joking. That'll cause chaos." Martha told them, shocked.

"Not chaos, change." Lazarus corrected her as if he were talking to a child. "A chance for humanity to evolve, to improve."

"This isn't about improving. This is about you and your customers living a little longer." The Doctor replied.

"Not a little longer, Doctor. A lot longer. Perhaps indefinitely." Lazarus said with a grin.

"Richard, we have things to discuss, upstairs." Thaw said starting to walk away.

"Goodbye, Doctor, Stella. In a few years, you'll look back and laugh at how wrong you were." Lazarus said taking Martha's hand and kissing the back of it then looked to Stella who as her hands clasped behind her and smirks at her before he leaves with Lady Thaw.

"Oh, he's out of his depth. No idea of the damage he might have done." The Doctor said as they watched him leave.

"You mean 'is doing.' They're going to sell that thing as is and not knowing a thing about the side effects." Stella said shaking her head. "You know they're not really going to test it, with all her money they'll just wave it through."

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

"Now? Well, this building must be full of laboratories. I say we do our own tests." The Doctor said looking excited,

"Lucky I've just collected a DNA sample then, isn't it?" Martha said as she held out her hand that Lazarus had kissed.

"Oh, Martha Jones, you're a star." The Doctor beamed making Martha smile back before they took off to the labs.

-0-

"I grew up over there. A tiny flat above a butcher's shop." Lazarus said as he and Lady Thaw looked out the office windows over the vast expanse of the city of Long at night.

"It'll have a blue plaque soon. Richard Lazarus lived here." Thaw said with a wide smile.

"It's gone. Destroyed in the war. The bombing." Lazarus said with a distant look in his eyes.

"Of course." Thaw said gravely.

"1940. Do you remember? Night after night. Explosions, guns, firestorm." Lazarus said with a haunted look.

"My parents had sent me to the country by then." Lady Thaw said.

"When the sirens went, we'd go to the cathedral there. We used to shelter in the crypt. The living cowering among the dead." Lazarus said bitterly.

"But look at what you've built here, now. You've laid the foundations for an empire. An empire we can rule together." She pulls him in for a kiss, and he pulls back in disgust. "Well, what's wrong?"

"Look at yourself, woman." Lazarus said taking her chin in his hand and moving her gaze to look into the reflection of the window.

-0-

"Amazing." The Doctor said as he starred at the image of the DNA strand through his brainy glasses.

"What?" Martha asked looking it over as well.

"Lazarus's DNA." The Doctor replied.

"I can't see anything different." Martha said.

"Look at it." Stella urged and as Martha took another look the DNA suddenly shifted, mutating before her eyes.

"Oh, my God. Did that just change?" Martha breathed out. "But it can't have."

"But it did." The Doctor replied leaning back.

"It's impossible." Martha said.

"And that's two impossible things we've seen so far tonight." Stella commented leaning back next to the Doctor.

"Don't you love it when that happens?" The Doctor asked with a smile.

"Beyond all reason." Stella said as she looked up at the Doctor returning his smile as he looked down at her.

"That means Lazarus has changed his own molecular patterns." Martha said breaking their locked gazes.

"Hypersonic sound waves to destabilize the cell structure, then a metagenic program to manipulate the coding in the protein strands." The Doctor explained and Martha gave him a confused look.

"Basically, he hacked into his own genes and instructed them to rejuvenate." Stella explained the Doctor's explanation.

"But they're still mutating now." Martha pointed out.

"Because he missed something. Something in his DNA has been activated and won't let him stabilize." The Doctor said looking at the DNA. "Something that's trying to change him."

"Change him into what?" Martha asked.

"I don't know, but I think we need to find out." The Doctor replied.

"That woman said they were going upstairs." Martha said.

"Then let's go." Stella said as they rushed out of the room.

-0-

"This is his office, all right." Martha said as they ran into the large office.

"So where is he?" The Doctor questioned looking around the office.

"Don't know. Let's try back at the reception." Martha said and they started to leave until Martha saw a skeletal leg with a ladies shoe on it sticking out behind the desk.

"Oh my…" Stella breathed out covering her mouth with her free hand the other firmly clasped in the Doctor's hand.

"Is that Lady Thaw?" Martha asked.

"Used to be. Now it's just a shell." The Doctor said as he looked down at the withered remains of the body. "Had all the life energy drained out, like squeezing the juice out of an orange."

"Lazarus." Stella accused.

"Could be." The Doctor replied.

"Who else do we know that's genetically altered himself and now has unstable DNA?" Stella retorted.

"Good point." The Doctor allowed.

"So he's changed already?" Martha asked.

"Not necessarily. You saw the DNA. It was fluctuating." The Doctor pointed out. "The process must demand energy. This might not have been enough."

"So he might do this again?" Martha asked.

"Mmm." The Doctor hummed.

"I wouldn't say might more like will." Stella said as they went out into the hall and into the lift just before another arrived.

-0-

"I can't see him." Martha said as they looked around the room.

"He can't be far. Keep looking." The Doctor said then looked over to Stella who pulled out a pair of silver open toed crystal flats from her clutch purse and changed into them then stuffed her heels back into the purse. "What are you doing?"

"Getting ready for the chase sequence we all know is coming." Stella replied.

"Might not." The Doctor replied, but Stella just shot him a look.

"Hey, you all right, Marth?" Leo asked as Martha looked around. "I think Mum wants to talk to you."

"Have you seen Lazarus anywhere?" Martha asked distractedly.

"Yeah, well, he was getting cozy with Tish a couple of minutes ago." Leo said not sounding too happy about that.

"With Tish?" Stella asked as she and the Doctor jogged up.

"Ah, Doctor, Stella." Francine said as she joined the group.

"Where did they go?" The Doctor asked Leo ignoring Francine.

"Upstairs, I think. Why?" Leo asked as Stella shoved her bag into his hand.

"Watch this for me Leo, thanks." Stella said quickly.

"Doctor …." Francine tried again, but the Doctor runs past her pulling Stella along with him hand in hand, spilling her drink all over her with Martha following them. "I'm speaking to you!"

"Not now, Mum." Martha called over her shoulder before she disappeared into the crowd.

-0-

"Where are they?" Martha asked as they reached the top floor.

"Fluctuating DNA will give off an energy signature." The Doctor said as he pulled out his sonic and began to scan around them. "I might be able to pick it up." He said then his face lit up in triumph. "Got him."

"Where?" Martha asked worried for her sister. The doctor pointed up. "But this is the top floor."

"The roof." Stella said in realization and with that they took off in said direction. They reached the roof just in time to here Lazarus finish a quote.

"I find that nothing's ever exactly like you expect. There's always something to surprise you. Between the idea and the reality, between the motion and the act…" Lazarus said, but was cut off by the Doctor.

"Falls the Shadow." The Doctor answered.

"The Hollow Men, by TS Eliot, nice quote." Stella commented.

"So the mysterious Doctor and Stella know their Eliot. I'm impressed." Lazarus said giving them a calculated look.

"Oh I know him alright, in more ways than one." Stella smiled in remembrance, the Doctor giving her a double take. Stella caught his look and gave him a shrug with a playful wink.

"Martha, what are you doing here?" Tish bit out.

"Tish, get away from him." Martha said reaching out to her.

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

"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 looking back to Lazarus.

"You're right, Doctor. One lifetime's been too short for me to do everything I'd like. How much more I'll get done in two or three or four." Lazarus's eyes gleamed at the prospect.

"Doesn't work like that. Some people live more in twenty years than others do in eighty." Stella replied shaking her head. "It's not the time that matters, it's the person."

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

"Or what a curse, look at what you've done to yourself." The Doctor tried to reason with him.

"Who are you to judge me?" Lazarus growled.

"Over here, Tish." Martha motioned to her sister.

"You have to spoil everything, don't you? Every time I find someone nice, you have to go and find fault." Tish said as she stomped up to Martha. Lazarus fell to the ground as spasms ricked his body.

"Tish, he's a monster!" Martha tried to explain.

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

"Yeah well she didn't fall for something that looked like that." Stella pointed out as Tish turned and saw the transformation in progress of Lazarus changing into a massive bony scorpion with a human face.

"What's that?" Tish gasped out.

"Run!" The Doctor yelled grabbing Stella's hand and pulling her along once again, but by now she was getting used to it, in fact she found herself reaching for him more and more.

-0-

The Doctor soniced the roof door shut and they run down the stairs as fast as they could.

"Are you okay?" Martha asked Tish.

"I was going to snog him." Tish replied as they ran into the hall with the elevators.

"EEEWWWW!" Stella grimaced before the lights started to slicker and the sounds of Lazarus banging against the door filled the area.

'Security one. Security one. Security one.' The lights went out and the doors all closed.

"What's happening?" Martha called out.

"An intrusion. It triggers a security lockdown. Kills most of the power. Stops the lifts, seals the exits." Tish explained.

"Oh, brilliant." Stella muttered.

"He must be breaking through that door. The stairs, come on!" The Doctor urged them down the stairs just as a loud bang followed by a menacing growl reached their ears.

"He's inside!" Martha said fearfully.

"We haven't got much time!" The Doctor said as they continued down the stairs.

"Then we should run faster." Stella pointed out.

-0-

"Tish, is there another way out of here?" The Doctor questioned as they ran back into the main room and up to Tish.

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

"Martha, setting fifty four. Hurry." The Doctor throws the sonic screwdriver to Martha. "Listen to me! You people are in serious danger! You need to get out of here right now!"

"Don't be ridiculous. The biggest danger here is choking on an olive." A woman scoffed.

"That's what you think lady." Stella said as the mutant Lazarus appears on the mezzanine, and jumped down, smashing a table causing panic to, of course, erupt all around them.

"Mum, get back!" Leo pulled Francine back. The mutant's tail sends a table flying hitting Leo who pushed his mother out of the way just in time.

"Leo!" Francine called out as the mutant stood over the frozen woman and opened its jaws sideways, then it bought its tail over, and another mouth appeared.

"No! Get away from her!" The Doctor yelled, but it was too late and a desiccated corpse falls to the floor.

"Leo. Leo." Francine said running to his side as the mutant turned to them.

"Lazarus! Leave them alone." The Doctor ordered.

"Get away from them." Stella yelled as she picked up a chair chucking it at Lazarus hitting him in the back. He turned towards the Doctor and Stella with an angry snarl allowing Martha to run to her family.

"Martha." Francine said when she saw her, her relief evident.

"Come on, stay with me. You're okay." Martha said holding Leo up starting to check him over.

"What's the point? You can't control it. The mutation's too strong. Killing those people won't help you. You're a fool. A vain old man who thought he could defy nature." The Doctor bit out in disgust.

"Only Nature got her own back, didn't she? You're a joke, Lazarus! A footnote in the history of failure!" Stella mocked as she and the Doctor lead the mutant off down a corridor.

"Stella, this isn't safe, you should go back." The Doctor said as they ran, but she just grabbed onto his hand.

"No, you don't have to do this alone." Stella said sternly. "I'm not going to let you be alone anymore…" The Doctor looked at her in surprise, feeling his hearts give a jolt. "…weather you like it or not."

"I like it." The Doctor replied after a moment of silence with a soft smile which Stella returned as they squeezed their hands tighter together picking up their speed to out run Lazarus soon losing him. They didn't stop running thought until they came to a room filled with pipes and control panels. They carefully made their way through it all making sure to not make a noise.

"It's no good. You can't stop me." Lazarus said as he searched for them.

"That is literally what everyone says that I have met so far with evil intent before we do." Stella replied.

"Is that the same arrogance you had when you swore nothing had gone wrong with your device?" The Doctor asked.

"The arrogance is yours." Lazarus said following their voices. "You can't stand in the way of progress."

"You call feeding on innocent people progress? You're delusional!" The Doctor said.

"It is a necessary sacrifice." Lazarus said getting closer.

"That's not your decision to make." The Doctor said with a glare.

"Peek a boo." Lazarus said hanging from the ceiling.

"Oh, hello." The Doctor said cheerfully.

"Wow, you are super ugly." Stella said before she could stop herself. The next moment found the Doctor and Stella running out and down another corridor. "Maybe I shouldn't have insulted him."

"You think?!" The Doctor replied.

"It slipped out." Stella defended herself.

"In here." The Doctor said pulling her into a lab.

The Doctor jumps on a bench and starts to take a light fitting apart, while Stella turns on a Bunsen burner and snuffs out the flame. They pull another tube off a gas fitting and hides behind another bench.

"More hide and seek? How disappointing. Why don't you come out and face me?" Lazarus taunted as the Doctor and Stella turn on as much gas as they can.

"Have you looked in the mirror lately? Why would I want to face that, hmm?" The Doctor asked.

"Oh so you get to insult him and I don't? That is so unfair." Stella pouted.

"We'll talk about it later." The Doctor and Stella run to the back door and the Doctor hits the light switch as they leave then KaBOOM goes the laboratory. The Doctor and Stella run down the corridor until they ran into Martha. "What are you doing here?"

"I'm returning this. I thought you might need it." Martha said holding out the Sonic.

"How did you…?" Stella asked.

"I heard the explosion. I guessed it was you." Martha replied.

"Good guess." Stella commented.

"We blasted Lazarus." The Doctor said.

"Did you kill him?" Martha asked.

"Define kill." Stella said as a roar echoed down the hall followed by Lazarus running after them.

"More sort of annoyed him, I'd say." The Doctor said grabbing the girls and pulling them down the hall.

"What now? We've just gone round in a circle." Martha said.

"Focus on the positive, we're alive." Stella pointed out.

"We can't lead him outside." The Doctor said as they ran back into the main room once again. "Come on, get in."

The Doctor pushed the girls into the sonic microfield manipulator chamber and quickly jumped in behind them, the mutant is outside.

"Are we hiding?" Martha asked.

"No, he knows we're here. But this is his masterpiece. I'm betting he won't destroy it, not even to get at us." The Doctor reasoned.

"But we're trapped." Martha pointed out.

"Well, yeah, that's a slight problem." The Doctor allowed.

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

"Yes, the plan was to get inside here." The Doctor answered.

"Then what?" Martha asked.

"Well, then I'd come up with another plan." The Doctor said.

"In your own time, then." Martha said.

"Hey!" Stella and Martha yelped as the Doctor searched his pockets.

"Sorry, sorry, sorry." The Doctor apologized.

"Well what you grabbed wasn't the screwdriver." Stella said crossing her arms as best she could over her chest with a narrowed look.

The Doctor blushed bright red, his eyes unintentionally glancing below her neckline before snapping up to her face. She gave him a raised eyebrow and his face went redder as he focused on retrieving his sonic screwdriver out of his inside pocket.

"Here we are." The Doctor said smiling in success.

"What're you going to do with that?" Martha asked.

"Improvise." The Doctor answered as he slid down to the floor and opened a panel, then started working with the wires and processors he found there.

"Enjoying the view." Stella asked with her eyebrow once again raised. The Doctor looked up in confusion, his eyes getting a good look at her long legs, then quickly back down with another deep blush on his face.

"I still don't understand where that thing came from. Is it alien?" Martha asked.

"No, for once it's strictly human in origin." The Doctor said.

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

"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 explained.

"So it's a throwback." Stella surmised.

"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." The Doctor nodded.

"It's like Pandora's box." Martha said.

"Exactly. Nice shoes, by the way." The Doctor commented.

"They are aren't they? Can I borrow them sometime when there's not some monster bent on destruction chasing after us?" Stella asked.

"So never." Martha said.

"Pretty much." Stella replied just as the machine started up.

"Doctor, what's happening?" Martha asked.

"Sounds like he's switched the machine on." Stella said.

"And that's not good, is it?" Martha asked.

"Well, I was hoping it was going to take him a little bit longer to work that out." The Doctor said.

"I don't want to hurry you, but I don't want to be a life sucking mutant or whatever I would change into." Stella said as the machine gathered speed.

"I know, I know. Nearly done." The Doctor said working faster.

"Well, what're you doing?" Martha asked.

"I'm trying to set the capsule to reflect energy rather than receive it." The Doctor said.

"Will that kill him?" Stella asked in concern.

"When he transforms, he's three times his size. Cellular triplication. So he's spreading himself thin." The Doctor said.

"We're going to end up like him!" Martha said in shock.

"You might, the Doctor's not human and I'm only part human so who knows what we'll end up like." Stella pointed out.

"Just one more!" The Doctor said then there was a big blast of energy that threw the mutant backwards. The machine stopped allowing the Doctor Stella and Martha to come out.

"So that's what it's like to be a sardine." Stella commented stretching her back.

"I thought we were going to go through the blender then." Martha said.

"Really shouldn't take that long just to reverse the polarity. I must be a bit out of practice." The Doctor said thoughtfully.

"Or you're going senile in your old age." Stella said playfully.

"Oi!" The Doctor said his lips twitching as he tried to hide his smile.

"Oh, God. He seems so human again. It's kind of pitiful." Martha said as they looked down at Lazarus laying naked face down on the floor.

"Eliot saw that, too. This is the way the world ends. Not with a bang, but with a whimper." The Doctor said with a sad look.

-0-

"She's here. Oh, she's all right." Tish said as she Francine and Leo ran over to Martha.

"Ah, Mrs. Jones. We still haven't finished our chat." The Doctor said cheerfully as he walked up to her only to get slapped hard across the face.

"Hey, what's the big idea?!" Stella snapped in surprise as gently placed her hand on the Doctor's cheek.

"Keep away from my daughter, both of you." Francine snapped at them.

"Mum, what are you doing?" Martha snapped.

"All of the mothers, every time." The Doctor said placing his hand over Stella's, her cool hand soothing his aching cheek.

"That suit really is bad luck." Stella commented.

"He's dangerous. I've been told things." Francine said.

"What are you talking about?" Martha asked.

"Look around you, nothing but death and destruction." Francine said gesturing around them.

"This isn't his fault. He saved us, all of us!" Martha argued.

"And it was Tish who invited everyone to this thing in the first place. I'd say technically, it's her fault." Tish elbowed Leo just as a big crash sounded in the direction the ambulance with Lazarus hand taken. The Doctor and Stella share a look then run off to investigate.

"Leave them." Francine said, but Martha shakes her head and follows the Doctor and Stella.

"Martha?" Tish said as she started to follow.

"Not you, too?" Francine said.

"Sorry." Tish said and ran after Martha.

-0-

The Doctor and Stella came up to the back of the ambulance which was open, and only contained desiccated corpses.

"Lazarus, back from the dead." The Doctor said.

"Should have known, really, with that name." Stella said as the Doctor scanned with the screwdriver.

"Where's he gone?" Martha asked as she ran up to them with Tish.

"That way. The church." The Doctor said.

"Cathedral. It's Southwark Cathedral. He told me." Tish said and they took off to the Cathedral.

"Do you think he's in here?" Martha asked as they walked into the church.

"Where would you go if you were looking for sanctuary?" The Doctor asked as they walk carefully up the nave to the altar and found Lazarus shivering behind it, wrapped in the red blanket.

"I came here before, a lifetime ago. 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." Lazarus said as the Doctor stepped forward motioning for the girls to stay back.

"The Blitz." The Doctor said.

"You've read about it." Lazarus said.

"I was there." The Doctor replied.

"You're too young." Lazarus shot back.

"So are you." The Doctor commented making Lazarus laugh, then his body makes painful cracking sounds.

"In the morning, the fires had died, and I was still alive. I swore I'd never face death like that again. So defenseless. I would arm myself, fight back, defeat it." Lazarus said in determination.

"That's what you were trying to do today?" The Doctor asked.

"That's what I did today." Lazarus corrected.

"What about the other people who died?" The Doctor asked.

"They were nothing. I changed the course of history." Lazarus said.

"Any of them might have done too. You think history's only made with equations? Facing death is part of being human. You can't change that." The Doctor said.

"No, Doctor. Avoiding death, that's being human. 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." Lazarus replied.

"Look at yourself. You're mutating! You've no control over it. You call that a success?" Stella asked as she walked up to the Doctor and Lazarus trying to get him to see reason.

"I call it progress. I'm more now that I was. More than just an ordinary human." Lazarus answered her.

"There's no such thing as an ordinary human." The Doctor said as Lazarus convulses again.

"He's going to change again any minute." Stella said quietly.

"I know. If I can get him up into the bell tower somehow, I've an idea that might work." The Doctor said in a sotto voice.

"Up there?" Stella asked following his gaze up.

"You're both so sentimental." Lazarus said then looked to the Doctor. "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. 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." The Doctor said sadly. Stella gently slipped her hand into the Doctor's squeezing it gently, empathizing with his pain.

"That's a price worth paying." Lazarus said.

"Is it?" Stella asked softly, a ghost of a sarcastic smile on her lips, her eyes distant and tired. "I never thought so."

"I will feed soon." Lazarus ignored her.

"I'm not going to let that happen." The Doctor said.

"You've not been able to stop me so far." Lazarus said.

"Leave him, Lazarus! He's old and bitter. I thought you had a taste for fresher meat." Martha taunted leading Lazarus away.

"Martha!" Stella called out as she ran after her friend ducking and pushing her away from Lazarus's grasp.

"Stella, Martha, no." The Doctor called out as Lazarus lunges for them as they ran.

"What are you doing?" Martha snapped as Tish ran with them.

"Keeping you out of trouble!" Tish replied.

"Good luck." Stella said then called down to the Doctor. "Doctor! The tower!"

Stella Martha and Tish run up the narrow spiral staircase ahead of Lazarus who has to keep stopping as he mutates.

"Did you hear that?" Tish asked.

"He's changed again." Martha said fearfully.

"Keep moving. We've got to lead him up." Stella urged the girls ahead of her as the Doctor goes back to the transept, underneath the central tower, and looks for them.

"Where are they? Martha?! Stella?!" The Doctor called out and Stella looked down from the passageway in the clerestory.

"Doctor!" Stella called down.

"Take him to the top. The very top of the bell tower, do you hear me?!" The Doctor called up.

"Up to the top!" Stella replied.

"Stella." Tish called out.

"Then what?" Stella asked.

"Stella, come on!" Martha grabbed her leading the mutant heading their way as the Doctor heads for the organ loft and gets out his screwdriver.

"Hypersonic sound waves." The Doctor said sticking the sonic into the socket and started pulling out the stops. "Inspired."

"There's nowhere to go. We're trapped!" Tish said as they came to the top of the tower.

"This is where he said to bring him." Stella said.

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

"He knows what he's doing. We have to trust him." Martha said.

"Ladies." Lazarus said with a smirk.

"Stay behind me. If he takes me, make a run for it. Head down the stairs. You should have enough time." Stella said standing in front of the others.

"But…" Tish started.

"You can't…" Martha said at the same time.

"Just do as I say." Stella snapped as the mutant tried to clamber across the gap under the bell, instead of going around the wooden frame. Stella broke off a chunk of the railing and swung hitting Lazarus hard across the face forcing him back, a gash cutting across his cheek and nose.

"I hope it's a good acoustic in here." The Doctor presses on both pedals and starts playing causing the mutant to start lashing with its tail, hitting Stella.

"Stella!" Tish and Martha called out as Stella hangs on to the bottom of the wooden walkway, screaming.

"Hold on!" Martha yelled.

"Get away from her!" Tish yelled as well.

"We need to turn this up to eleven." The Doctor said.

The organ notes reverberate, hurting the mutant as well as Tish Stella and Martha. Stella starts to lose her grip just as the mutant falls to the cathedral floor below. The Doctor stops playing when he hears the crash, and goes to look. A naked man is lying on the flagstones amid a shower of broken wood. Stella's fingers slip just as Tish and Martha grab her wrists.

"We've got you. Hold on." Martha said as they pulled her up and into a tight hug.

"Stella? Martha?" The Doctor called up.

"We're okay!" Stella called down. "We're all okay!"

"That was a close one." Martha commented.

"Thanks for the save." Stella said.

"It's your Doctor you should be thanking." Tish pointed out.

"Oh I will." Stella said with a nod.

"I told you he'd think of something." Martha said.

"Never doubted him." Stella said.

"He cut it a bit fine there, didn't he?" Tish commented.

"He always does. It's more fun that way." Stella said with a breathless laugh as she stood up and began to make her way down the stairs.

"Who is he?" Tish asked.

"He's, he's the Doctor." Martha said.

"Well whoever he is, he's really captured that Stella girl's attention and I think the feeling is mutual." Tish commented not knowing the effect it had on Martha.

-0-

Stella ran down the stairs finding the Doctor kneeling down next to Lazarus's body. Stella walked up to him as the Doctor closed Lazarus' eyes and he turned back into an old man. She gently placed a hand on the Doctor's shoulder knowing that anyone's death hurt him, good or bad.

He stood up and looked down at her his eyes impossibly sad as she pulled him into a tight hug. He laid his cheek against the top of her head and surrendered to the comfort of her hug. Martha and Tish arrived just as they pulled apart, Martha feeling a pang of jealousy. It seemed they were getting much closer.

"I didn't know you could play?" Martha said walking up to them.

"Yeah, we should do a duet sometime." Stella said with a smile.

"Oh, well, you know, if you hang around with Beethoven, you're bound to pick a few things up." The Doctor said off handedly.

"Hmm, especially about playing loud." Stella said rubbing one of her ears.

"Sorry?" The Doctor joked as he leaned forward making the girls laugh.

-0-

After everything had been cleared up they had all gone back to Martha's home, the Doctor and Stella changing back into their street clothes. Stella could only hope that her plan had worked, that maybe she and Stella would get to travel with the Doctor some more. She felt that he really needed them and she wanted to be there for him.

"Something else that just kind of escalated, then." The Doctor said as the girls watched him unlock the Tardis.

"I can see a pattern developing. You should take more care in the future. And the past. And whatever other time period find yourselves in." Martha said.

"It's good fun, though, isn't it?" The Doctor commented.

"Yeah." Stella said resting her hand against the Tardis, feeling her heart break a little at the thought of never seeing her or the Doctor again, unless she had managed to change his mind.

"So, what do you say, one more trip?" The Doctor asked looking between the two girls.

"No. Sorry." Martha said shaking her head.

"What do you mean? I thought you liked it." The Doctor pointed out.

"We do, but we can't go on like this. One more trip. It's not fair." Stella said looking up at him.

"What're you talking about?" The Doctor asked in confusion.

"We don't want to be just a passenger anymore. Someone you take along for a treat. If that's how you still see me, we'd rather stay here." Martha said as Stella nodded in agreement.

"Okay, then. If that's what you want." The Doctor said and Stella let out a breath of air, a smile forming on her face.

"Right. But we've already said goodbye once today. It's probably best if you just go." Martha turns her back, but he just stands there. "What is it?"

"What? He said okay." Stella pointed out.

"Sorry?" Martha looked between Stella and the time lord.

"Okay." The Doctor nodded towards the Tardis.

"Oh, thank you, thank you!" Martha chanted as she hugged the Doctor followed by Stella who was just as excited.

"Well, you two were never really just passengers, were you? And I always promised Stella could travel with me, about time I lived up to it." The Doctor said as they go into the Tardis, and it dematerializes just before the telephone rings.

"Hi, I'm out. Leave a message."

"Martha, it's your mother. Please phone me back. I'm begging you. I know who this Doctor and Stella really are. I know they're dangerous. You are going to get yourself killed. Please, trust me. This information comes from Harold Saxon himself. You are not safe!" Francine begged.