"Answer me this. Did I...did I make a difference? My life, and my...my death...was I worth it? Did my life really matter?"

"Yes. You were brave. You were good. You mattered."

It was both a lie and not a lie. This victory, this war the little human fought so hard to win, could not have been won without her. Yet in the tapestry of time and space, this war was but the smallest tangle in the fabric, and her life the slenderest of threads.

Perhaps I have become sentimental, for I could not tear my gaze away from this tangle of timelines that smaller beings call a war, and the one timeline that was cut so short.

The spiral of the Time Vortex flared with light and music, and the Bad Wolf came galumphing from its depths. I had seen her mark before, in the residue of the ash that remained of the Daleks' post-Time War attempt at empire. I always knew, in the abstract, that there were powers greater than mine and my adversary, Crayak's. Never before had I encountered such a power myself. She had all the power of a timeless fixture of the universe, and all the passion of a single human girl.

I trembled.

The Bad Wolf inspected the frayed-off timeline that had once been a girl named Rachel Berenson. Her eyes were like the nebulae from which stars are born. The girl who is a part of me would like her. Their timelines ought to meet.

That would be in violation of the Law of this universe, I said carefully, knowing that she could rend the spacetime tapestry before me with a swipe of her terrible claws.

The Bad Wolf bared her teeth. Each one was sharp enough to puncture holes between dimensions. I can do anything.

I shuddered, and followed her gaze to the steel cable that ran through the flexible strings of time. It was the timeline that could never be cut: the Anomaly. I was suddenly filled with the terrible knowledge that the Anomaly had been her doing.

I saved him because I love him, the Bad Wolf said.

I thought of the human whom I had just accompanied through her last moments. She died defending freedom; so had the man who would become the Anomaly. He might have asked the same thing before he died, except he knew his sacrifice mattered. He understood the cause for which he fought, and gladly gave his life for it. The Bad Wolf had taken that sacrifice from him. He would never get another chance to give his life for something he believed in, and I could see that one day, he would lose everything except his life.

You didn't save him. You damned him.

I saved him because I love him, the Bad Wolf repeated. And because it was necessary.

When I looked closer at the Anomaly, I noticed a halo around it - millions upon millions of tiny gossamer threads that wrapped around the unbreakable steel, all the lives bound up in his. The Bad Wolf tugged on the tapestry with her paw, as if to take it apart, but even she could not. Through all the myriad connections of the universe, every thread in the tapestry was anchored to the Anomaly and could not be torn away. At the cost of grief without end, of watching everyone and everything turn to dust, the Anomaly held the fabric together. I realized that the Bad Wolf chose this man for a reason. So many threads touched his, however fleetingly. He brought the tapestry together because of his endless capacity to love.

I still feared the Bad Wolf. What she had done filled me with terrible awe, and I feared what she might yet accomplish. But I saw that she did everything by design.

The Bad Wolf returned her attention to the war, and Rachel's death. They cannot meet by the Law of this universe, but it is permitted by the Law of another. She looked up at another web of Time shimmering above her. It shall be done.

Rachel ran.

She felt sick at heart, disgusted with herself. Jake, her cousin, had just tripped and fallen. There was a monster coming up behind them, blades ready to rend and slice, and she left him behind. Even now, his blood might be running across the broken, weed-choked concrete.

Up ahead: a flash of yellow. There was a woman, in her early twenties maybe, with hair like a sunbeam in the darkness. She stood, watching. Rachel wondered, suddenly, if she was the only one to make it out of the construction site alive.

The blonde woman spotted Rachel. Fear flared anew in her chest. What if she was one of them? But then there was a roar from one of the bladed monsters, and the blonde's eyes widened. She looked back over her shoulder, and beckoned for Rachel to follow her. For some reason, she did.

Rachel followed the edge of the woman's coat, the only part of her she could see as they darted around dark corners. Finally, she found herself in the parking lot of a Burger King, open 24 hours. The woman was there, her face illuminated by the neon lights in the windows.

"Who are you?" Rachel demanded, after she'd caught her breath.

"I'm Rose Tyler." Her eyes were dark with mystery. "I've traveled the stars and seen the planets that you now know are real. I'm going to help you save the world."

And for a moment - one starlit moment - Rachel believed that together, they could.