The snow crunched under Zoe's feet as she stepped out of the TARDIS.

"Where are we, Doctor?" Jamie asked, the breath coming out of his mouth like a cloud of steam. The Doctor forgot, sometimes, how warm humans were.

"The far future, I believe," he answered. "According to the TARDIS, this is London."

"Ah, no it's—" Jamie began in disagreement.

"The far, far future," the Doctor reminded him. He watched his two friends look around the ruins of the once great city, black against the wintry weather. The scene was lit by a faint, waning moon, reflected in the snow. Two pairs of dark eyes followed the twisted, burnt-out spires upward to the sky.

"The stars…they're the same," murmured Zoe in some kind of wonder. The Doctor looked up as well and indeed they were. It would take much longer than the span of human civilization for the stars (or, rather, the Earth's orbit) to move enough to be noticeable. Another reminder of the fleeting nature of all things: nothing can last.

He frowned to himself-this was all too existential for him, but he wondered at the uncomfortable feeling the bleak scene gave him. After all, who knew better than he that everything comes to an end if you journey far enough into the future? And yet, it had never bothered him before as it did now. London had been just another city, humans just another semi-evolved species, until he'd been forced into close contact with them. And they had surprised him—so compassionate, so brilliant, and too easy—much too easy, especially since his regeneration—to love. He realized that he'd begun to think like them: in the present, forgetting the way he'd been taught to see civilizations: as a part of time, passing, finite.

And here he stood in what had once been a teeming metropolis, bustling with silly little individuals and their silly little individual lives. When had he started considering such cosmically insignificant people and ideas to be so important? Because they were. And in this far off future all the things they'd built, all the philosophies they'd argued, all the music they'd written, all they'd ever done was gone.

It made him unaccountably sad.

They had thousands of years, he reminded himself, thousands of years in which to do the things humans do: believe, invent, love, live. Build and tear down and build again. Kill each other and save each other. Be.

And, if nothing else, he would remember.

He pulled his mind back to the present and considered his two human friends: Jamie, musician-come-warrior, who looked at the universe through wide eyes and Zoe, mathematical genius, who'd been taught to be logical and was learning to feel.

They were human, wonderfully, bewilderingly human. He could see they were both genuinely bothered by the scene before them, even though neither was from London. Not that that mattered—the whole earth was as desolate as this place. Zoe's eyes were strangely bright. Jamie was looking at his feet.

The Doctor put an arm around each of their shoulders. "Come on," he said quietly. They returned to the TARDIS.

A minute later, all that remained were footprints in the snow.