"And all they found was the footprints leading away from the collapsed rail bridge - a single set of footprints that started out as human...and ended up as those of a gigantic hound." They were both quiet for a moment, the firelight casting odd shadows across Miranda's face as she looked darkly at the Doctor, waiting for his reaction to her tale of terror.

"Not bad," he finally chimed, apparently not at all terrified. "But half of the effect of those tales is in the atmosphere. Hard to believe a tale of shape-shifting horror in the deep woods when you're an alien sitting on a TARDIS in deep space."

She huffed. They'd been at this for a while - a few months at least; she'd wrack her brain for a good ghost story from her childhood to try to get a rise out of him, and he would laugh her off, then counter with a story of his own. His were always worse, and she often had to make sure he didn't leave her sight until she'd fallen asleep, or, for the more terrifying ones, she'd demanded they go to bright, fun locations. More often than not, that meant they saved the day for the inhabitants of said bright, fun location, but it was still better than being in the dark.

When he'd told her about the Vashta Nerada, they'd gone to a planet with seven suns, that was balanced in the gravity of all of them, and so there was no night. Ever. She'd seen their work in her nightmares on the TARDIS, and just couldn't shake it.

"So how are you going to one up me this time? A little atmosphere?" She was teasing, but his eye caught the adventurous glint she was used to.

"Atmosphere's what you want? I'll give you atmosphere." He popped up from the rug where they were sitting in front of the fireplace and dashed out to the console room.

Miranda chuckled quietly, pushing herself up off the ground slowly to follow him. She usually waited until he was gone to get up from the floor, or let him gallantly help her. It had been a long time since she first set foot on the TARDIS, and though the nanogenes still mended her skin quickly enough, they were weaker and older now, just like her. She glimpsed her reflection in a piece of glass, and paused to look at the transparent image. There were no wrinkles, and perhaps she looked on the outside like the 29-year-old she had been when she first joined the Doctor, but she ached as she hadn't before. She was still human, and he was still a Time Lord, and no matter how many times he promised her forever, and she promised him the end of time, they both knew it was a lie.

She sighed, biting the inside of her lip to force away tears. That, after all, was her deepest fear. That after years of life with him, she'd have to go away. That despite the fact that his face had started out so much older than hers, she would eventually bypass him, and die. Even if the nanogenes made her an ageless Snow White, she would still have to bite the poisoned apple of human mortality. There was no horror story that matched the terror of such fairy tales for her.

The Doctor was busy at work in the console room - flying between levers and pullies and buttons, the familiar sound of the TARDIS humming through her mind and buzzing through the air. She'd had a moment ageswhere the TARDIS seemed to show her how to fly, and the Doctor had filled in the gaps in her memory. The strange hum in the back of her mind was more discernible that day, and it seemed to tell her what to do - and then she had done it. It was easy, almost predictable, and she now sometimes teased the Doctor that she was a far better driver. She flicked a few switches to transfer power to the stabilizers - the Doctor often conveniently forgot this step - and settled herself against the railing to watch him work. "Where are we going?"

"Oh, I was thinking the Black Ages of Arboranthum. It's a tree home world, one of three. This one's good for hardy trees that like cold. Huge trees, too, near the equator. Like walking, talking redwoods."

"So like ents."

"Ents?"

"Lord of the Rings. Come on, you've read Lord of the Rings, right?" He shook his head, not quite making eye contact with her. He was usually far more cultured than her on every planet and time they went to. Only a few times had she shown him up - once in Victorian Scotland they'd run into Mrs. Margaret Oliphant, whom Miranda had engaged in a long discussion about her novellas while the Doctor waited rather impatiently. He'd later complained that had there only been a copy of the story in question handy, he could have read it within a few moments. She'd teased him for being a poor sport before making it up to him. He hadn't complained then.

"Erm, I mostly missed the Tolkien rage, I suppose." He looked chagrined, and she chuckled and ran her fingers through his short hair.

"No worries. You can read it next time I nap. It'll be something to occupy your time instead of tinkering with the nanogenes. Seems to upset the TARDIS."

"She's not upset!"

The console made a short whirring noise that very definitely sounded miffed. Miranda's lips turned upward in a smirk. "You were saying?"

"Just trying to see what makes 'em tick. I'll make it up to her."

"Right." Miranda pressed her hand to her lips and then against the metal of the console. "So are we there yet?"

"You that anxious to be terrified witless by the shadow forests?"

"I'm ready to go exploring, if that's what you mean."

He walked out of the TARDIS ahead of her, his arm lagging behind him so that she could take his hand. They were in the middle of a deep forest. The trees were well spaced, as though arranged in rows, and stood hundreds of feet high. The TARDIS was tiny by comparison, making her even tinier. It felt like they were scowling down at her, and she was glad for the Doctor's hand. "This enough atmosphere for you?"

"It's a start." She straightened up and mustered her confidence. "So you going to tell me the tale as we walk? Or do you have a particular destination in mind?"

"No place in particular. Just setting the mood." He twined his fingers with hers and grinned.

"You know, when you say that, I feel like you're a teenage boy who takes his date to the slasher flick so she'll let him put his arm around her."

"They do that?"

"It's a bit of a cliché, yes."

"Smart boys then." He grinned at her again, and it was contagious, even in the heavy dark of Arboranthum. She smiled back at him, and for a moment she saw his whole history in his gaze - other pairs of eyes smiling back at her. She forgot sometimes that her Doctor was not the only version of himself. He'd been old. He'd been a father – a grandfather. He'd saved worlds and destroyed them. He'd been debonair and goofy and deadly and gentle and diabolical. He was the whole universe wrapped up in one man, she thought. She leaned over and kissed his cheek. "What was that for?"

"Dunno. Just wanted to." She shrugged and kept pace with him. She closed her eyes for a brief moment when he kissed the top of her head. It was an oddly sweet moment for him. She had gotten used to the manic bounces between raging intensity and quick humor, between letting the universe pass around him and being the center of it. Gentleness was not her Doctor's strong suit. She loved him, but treasured these moments, a small part of her knowing that they were glimpses of a past and a future she would not be allowed to see.

They walked in the growing darkness, and she imagined that even the tops of the trees were cloaked in blackness now. The chill in the air began to creep down her spine and she shivered. "There we are. Now I can start telling you tales of terror. A mite more believable here, wouldn't you say?"

"We'll see. I'm still pretty proud of my old lumber mill horror story."

"You would be. So imagine that you're in a place a lot like this – ancient, dark, full of beings you don't even know are sentient, perhaps. Rumors are that the rocks can talk between themselves, and every groan of the wind through a crack has you checking your back. You've crash landed your ship after a sunstorm, and you're the only surviving crew member…"

As it turned out, the Doctor was right. Atmosphere made all the difference. That tale, not actually so dreadful on it's own, was made downright terrifying by the swaying of branches and the scuttling of things in the underbrush. She wanted simultaneously to punch him and cling to him. "We are lighting a giant raging fire in the fireplace when we get back to the TARDIS. How far out are we?" She looked around for the familiar blue shape, but couldn't see it.

"About a ten minute's walk. You want to head back? If I'm not wrong, the old Arboranthine temple isn't far ahead. Grand architecture carved purely out of stone."

"Wood would be a disturbing choice, huh?"

"Precisely! So you want to go then? Fantastic!" He clutched her hand tighter and set off. "Now, you see, the trees weren't always sentient. They're DNA got mixed up with some human stuff, as well as some other sentient plant matter, and then evolution happened and well, the Arboranthines were the first to develop. The most tree-like, as you're used to them on earth. Sentient, but slow-thinking. Still, when they live hundreds of years, you can afford to think slow."

"So slow thinking's a common problem for beings that are hundreds of years old?" She stuck her tongue out at him as he frowned at her.

"Here we are!" He gestured toward the monument - hundreds of feet high, like a great Tower of Babel that reached impossibly into the sky.

"Almost as tall as the Star-Touching Temple on Barcelona."

She frowned. "That was not such a great day."

"Nonsense. It was the day I knew I was gonna keep you around."

She looked at him skeptically, the creaking noises of the forest making her take a step closer as they walked toward the structure. "Really? Seemed more like the day I got drunk on a foreign chemical, played with guns, and blew up a factory. Not a high moment in my career."

"Can't always be perfect."

"Unless you're the Doctor," she teased.

He stopped, putting his hands on her shoulders gravely as he faced her. "Especially when you're the Doctor." His eyes widened suddenly, and she barely had time to register the look of fear on his face before he threw her sideways. She hit the ground hard and felt her arm crumple underneath her as she failed to break her fall. The creaking sound of the forest was amplified, roaring around her now as she tried to come to grips with what she was seeing. The trees were moving, trembling like children before a powerful and frightening monster.

And it was truly tree that was moving was massive - she and the Doctor had been to entire worlds that were smaller than this beast. It moved gracefully, a feat for something of its size. It was wondrous, but she couldn't waste much time examining it. "Doctor!" She cried out for him, his form lost to her from where she lay in the underbrush. "Doctor where are you?" She held out her hand blindly as she struggled to her feet, hoping for the familiar feeling of his fingers twining with hers with the unspoken command to run. Her eyes desperately scanned her surroundings for the familiar black jacket. She didn't see it.

The earth thundered as the giant tree stepped forward, and Miranda was thrown to the ground again, her head full of thunder and new parts of her body ringing shrilly with pain. "Doctor! Please!"

The whole world seemed to be waiting to be crushed under the monstrous movement of the tree. Her mind raced - then it began to hum. The thundering was still there, echoing through her mind, but the expanse she hadn't felt in years was there now, forced out in a violent ballooning of sensation. She didn't only feel her surroundings - she felt everything. The lullaby soared through the cathedral-like space of her brain, and she thought of the Doctor. Images that were not hers accompanied her thoughts: her walking with the Doctor, the Doctor shoving her away, his own body flying the other direction with the shudder of the earth. His head connecting too-solidly with the ground - the rock beneath the thin layer of moss. He didn't stand again. He was still lying there now. Now, as the tree moved in terrible circles, confused and tormented just as they were. The Doctor was still alive, but...

She felt the pain sear through her. Not her pain, but she screamed anyway. High and loud and long, the scream ripped out of her and for a brief moment, the tree stopped. The pain in her mind was not hers, but she felt it. She realized that the tree could feel it too, and had stopped, checking itself for damage. She tried to push the pain away, and the tree moved. The Doctor was beaten, the weight of a few branches having snapped his legs. She felt that. She screamed again, amplifying his pain in her head. If she stopped, if she lessened his pain, the tree would move again, and they would both die. She heard the Doctor's own pitiful moans and wished she could stop. She had to get him out of there, but his weight was dead - mostly unconscious, and with his legs out of commission - and her wrist was surely sprained or broken.

She clenched her teeth. There was nothing for it; it had to be done. She slipped her body next to his, holding her arm awkwardly as she tried to both use it and protect it. Finally, she got the bulk of him on her shoulders. Muttering a quiet apology for how badly this would probably hurt, she pulled him with her, dragging his body more than she would like, knowing that each jolt of his legs against the ground was excruciating. She could feel that - his pain passed through the air to her mind, newly raw with the burst of telepathy from both of them. She heard the tree start to move and feared the worse, hunkering them down by a large rock she could only hope would break the tree's step. The sound of a crash further away alerted her to the fact that it was leaving, that they weren't going to be crushed to death. She took a deep breath.

The Doctor was out cold, the pain having just been too much for him. She kissed his forehead, then looked around for something to brace her wrist with, finally settling on a piece of a branch that seemed rather sturdy. She wrapped it with a piece of her shirt, then sat down next to the Doctor to see how badly off he was. She looked at his jeans lightly touching them, and recoiling when she felt the brokenness beneath them. She kissed his forehead again, steeling herself against the pain that was surely to follow. She hoisted him up again, this time bearing his weight on her arm.

She began to hum the melody to the lullaby, focusing on that, letting the pain pass through her. She moved with the melody, and soon words formed on her lips. Quiet words that didn't even make sense, but they distracted her from the pain, and walking was easier. The sounds seemed to vibrate through her, moving the song from her mind through her entire being. Ten minutes, the Doctor had said. A ten minute walk at normal speed. It seemed like hours before she saw the TARDIS' welcome blue exterior.

When she finally collapsed after depositing the Doctor on the bed in the medical bay, she gave herself a moment to breathe before speaking softly to the TARDIS, whose worried hum was hard to ignore. "Emergency protocol 17. Earth's moon. Please." She was gasping for breath between each statement, and she heard the engines whir to life before she had even finished. She took a minute to patch herself up first before turning to the Doctor. To her surprise, the ambient nanogenes seemed to spring to life. She pulled off the makeshift splint and blessed the little machines as she gently flexed her fingers.

She turned to the Doctor, using a pair of scissors to cut away his bloody jeans. He'd be upset about that, but they could argue about his damaged clothes later. She wrinkled her nose. The sight wasn't pretty. The weight falling on his legs had been significant, and the damage was visible. As she exposed the wounds, though, a faint golden glow seemed to dance around them - nanogenes.

She nearly cried with joy when she realized what was happening. His tinkering, his boundless curiosity about what makes things tick, was paying off. The gold swirled around his legs, and she stood by, watching to make sure all was going well. She managed to remove his jacket and jumper, along with the ruined jeans, hanging up the first two and tossing the latter in the bin. Keeping an eye on the golden glow - she could see his bone mending - she wet a cloth to put on his brow. The pain had taken its toll, and a sheen of sweat covered him.

Then there was only waiting. She rested her head next to his, feeling her adrenaline trail off into exhaustion. She blinked for a long moment, and when next she opened her eyes, the work on the Doctor's legs was nearly complete. She smiled sleepily, pressing a kiss to his forehead before dozing back off.

She dreamt of infinity. She'd never seen so much all at once, even in the heart of the TARDIS. Unbounded in time or place or perspective, she saw everything. Her mind was filled with it. And once again she found him as a lifeline. She traced the shape of his timeline, fissured and fractured as it was, and it felt familiar. It felt like home.

While they slept, the miraculous little robots were doing their job. Every bone mended, every bruise healed, every scar smoothed over. Due to the Doctor's dabbling, they had been familiarized with all that superior Time Lord physiology, and didn't seem the worse for having to conquer the triple helix structure. They crept up the Doctor's unconscious form, mending it as they went, sorting out the parts of him that travel through the vortex was damaging.

They reached his head, leaving off their work on him, but being the intuitive creatures that they were, they recognized another being touching him, something that they vaguely recognized in their programming. Gold specks danced around her face as she dreamt of eternity, trying to confirm what they knew of this species. Human traces... time lord traces... Brilliant though they were, they couldn't quite confirm.

Then they encountered her mind. From the processes occurring, the little machines could only match them with the genetic information present in their upgraded coding - Time Lord. The information spread quickly through the entire microscopic fleet - Time Lord, Time Lord, Time Lord... Each strand of DNA was wrong. Each helix needed another addition. The nanogenes had their work cut out for them.

And the Doctor and Miranda slept on.