a/n: This is inspired in part by a quote I read from Stephen Moffat saying that Matt Smith's Doctor was really the thirteenth due to the previously unknown War Doctor between the Eighth and the Ninth, and by the idea that the Tenth Doctor used up an extra regeneration through the meta-crisis.

The Moment

Time isn't a straight line, Clara. You of all people should know it's all wibbly wobbly, bendy wendy. You lot think it's all about cause and effect, action and reaction. It's not. Sometimes the effect and the cause are simultaneous. Sometimes the reaction happens before the action…

I've seen my grave at Trenzalore. My final resting place. Where I will ultimately die without regenerating...

Time Lords are allotted twelve regenerations, thirteen lives. Well, I've already regenerated twelve times. This is it. This is my thirteenth life. My last life…

The fabric of time hung like a tapestry front of her. In this form, the form subconsciously chosen above all other forms by the Doctor, she could see everything. All that is, all that was, all that could be. All in front of her. Most threads flowed along a straight path from their beginning to end. Others interwove back and forth, up and down, joining others for a bit before breaking off on their own again. Periodically she could see the intersection of a number of threads tied together into an unbreakable knot—fixed points—but there were far fewer of those than one would expect.

She looked closer. If she looked very carefully she could see a single blue thread woven in and out, up and down, back and forth, retracing its path, joining with other threads and then traveling alone, occasionally disappearing from sight only to reappear in a completely different part of the tapestry. It was far longer than most of the others in the tapestry, but even it had a beginning and an end. Her brow furrowed. It seemed to end at a place called… Trenzalore. As she contemplated the ending of that thread, she became sad.

Sadness. That was… odd. She was merely the interface of a sentient weapon, wasn't she? She may have a conscience, but that didn't mean she had an emotional connection to the biological life forms around her. She shouldn't have emotions at all, and particularly not for the Time Lord who had stolen her and was contemplating using her to commit genocide.

But in this form she did have an emotional connection to him. That was a fact. Was it because she had taken on this form, a form who had cared for him, or was it more? Had this form taken on her to interact with him? Was she not only an interface for the Moment, but an interface for this… Bad Wolf whose form she had taken on?

She snorted. It was irrelevant. The conundrum of the chicken and the egg. Currently, while she had this form she was both—Moment and Bad Wolf—with the knowledge and power, and evidently feelings, of both.

She examined the tapestry further. The Time Lord, the Doctor, had decided to try to save Gallifrey rather than destroy it. That was good, she thought. She didn't want to be used to commit genocide, to kill so many innocent lives. But what he was doing wasn't enough. Even with the help of all his previous incarnations, he wouldn't succeed. If he just had a tiny bit more help…

She reached out and touched the end of the thread, and slowly she smiled.

In the TARDIS, an older man lay, motionless and not breathing, on the hard metal grating of the console room floor. His blue-green eyes suddenly flew open and he inhaled in a long, loud, painful sound. He sat up abruptly.

"I'm alive!" he exclaimed, tentatively exploring his face with his fingertips. Thick hair, hawkish nose, bushy eyebrows… "I'm alive? But I died. How am I alive? And what was I doing on the floor?"

"Less risk of falling that way," came a familiar voice from behind him.

He twisted around. Behind him a young blonde woman, her clothes in tatters, was sitting on the railing that surrounded the center console. Her hands rested on the railing on either side of her while her legs, crossed at the ankles, swung back and forth. His hearts stuttered.

"If you had been formed standing up or sitting on the chair, you could have fallen and hurt yourself," she continued.

"Rose," he gasped.

She looked puzzled.

"No," she said, shaking her head. "Yes? Maybe? That one is a tuffy. I still feel I am called something else in this form, but somehow Rose sounds correct as well."

"How are you here?" he asked as he stood up. "More to the point, how am I here? I used up my regenerations and I died."

She nodded, an exaggerated gesture that appeared more like a bow than anything else. "Yes, you did."

"But I'm alive."

Another nod. "Yes, you are."

"But I died. I shouldn't exist now."

"But I died. But I'm alive. But I died," she said mockingly. "You're beginning to sound like a broken record."

"But I don't remember regenerating."

"That's because you didn't. Haven't. Yet."

He stared at her. "If I haven't regenerated, then how am I here?"

She rolled her eyes. "For someone who considers himself a Lord of Time, you certainly are a linear thinker. You died before, and now you didn't," she told him. "You will regenerate, but you haven't yet. This you is a future version, a possibility, a potential, waiting in the wings, only coming into existence if the right circumstances are tweaked." She held out her hand and seemingly plucked something from the air in front of her. "And I… tweaked them." She gave him a cheeky grin.

"You can't do that!" he protested.

"Yes, I can," she said indignantly. "I'd say the fact that you're here proves that I can."

"No, I meant you shouldn't! It's wrong!"

She raised her eyebrows. "This version of you is quite a hypocrite, isn't it? It's all right for you to go mucking about in other people's timelines, but as soon as someone does it with yours…" She let out an exasperated sigh. "It's a good thing you're cute or you'd be completely insufferable." She winked at him.

"Rose…" he began.

"No," she said seriously. All her previous flirtation was gone as if it had never been there. "Not Rose. Not entirely. Bad Wolf."

And as he watched her brown eyes briefly shone with a golden light, the sight of which made him both slightly terrified and oddly comforted.

"Rose, why? Why did you do this?"

"You need your help," she told him. "The others are not enough. They will fail without you."

"I don't understand."

Suddenly she disappeared from the railing in front of him only to reappear next to him. "Gallifrey," she whispered in his ear.

Still puzzled, he turned to face her, and then his eyes flew open wide.

"It's time, isn't it? This is when I'm trying to save Gallifrey?"

"Yes," she said. "All of you, working as one, trying to save the planet of your birth."

"But I failed," he protested. "I tried and Gallifrey was destroyed anyway."

She reappeared on the railing. "Yes, it was and it is and it will be… without your help."

"And with my help?"

"Who knows?" She shrugged. "Why don't you go find out?"

She disappeared from the railing again.

"Wait! Wait!" he cried desperately, and she reappeared, this time standing in front of him. He reached out to touch her, and his hand passed through her.

"I'm sorry," she said apologetically. "I'm just an image. No touch."

She reached up and cupped his face, and he imagined he could feel her skin against his. Then she leaned forward, and despite her assertion that she was just an image, he could feel her lips gently press against his. He closed his eyes and sank into it.

After a moment he felt her pull away, and he heard her voice quietly echo in his ears.

"Good luck, my Doctor."

He opened his eyes. He was alone in the room. She was gone as if she had never been there.

He took a deep breath.

"Right," he said decisively and moved around the console to set the coordinates, coordinates he could remember from his past life.

He materialized above Gallifrey. On the monitor he could see twelve other TARDISes encircling the planet, each from points in his previous lives. Over the speaker he could hear a voice exclaim, "It's all twelve of them!"

"No sir," he responded as he lowered a handle on the console. "All thirteen!"