He's not sure what they're talking about. All he knows is that they're exchanging stories, writing them down to be put in the TARDIS library. Something about Amy wanting fairytales to tell her children when (if) they visit her "magic Doctor"… should she have children, that is.

Koschei is moderately sure he's supposed to be Amy's sounding board as the Doctor writes, but he doesn't care enough to really pay attention. He just keeps skimming through photo albums with the sounds of the typewriter and Amy's Scottish tones as background music. But then he hears something. Something familiar and strange and… it couldn't be, right?

"…a crack in my bedroom wall. Like a crooked smile and I could hear voices from it - Prisoner Zero has escaped," she puts on a stuffy posh accent for that, which would have made Koschei laugh if he hadn't been so focused on what she was describing. "It was huge! Almost as tall as I was back then, and I was no short-stuff even at seven. Two parts in time that should never have touched, isn't that what you said Doctor?"

The typing pauses for a second. "I think so, yeah," the brunette replied distractedly. Koschei blinked, eyes snapping to Amy.

"What do you mean a crack?" He asked suspiciously. His mind flashed back to that damnable cell, to Gallifrey, and he could still remember every detail. The way the chains sounded with his every move, how his voice echoed, and most of all how there was a crack on the wall like a politicians crooked smile. "Did it glow?" That's one thing he remembered. He remembered it glowing, just faintly, and voices coming from it. Now that he looks back voices that sounded oddly like Amy and Rory…

Amy shrugged in response. "It was just a crack, you know? Like," she paused. "Sort of shaped like this." She motioned in the air with her hands and Koschei drew the picture in his head. It was exactly like…

"It's like the crack in my cell!" He blurted. The Doctor's head snapped up.

"What?" he said confusedly. Amy could only blink. Koschei grinned inwardly. Finally, after all those months, an explanation!

"There was a crack back in my cell on Gallifrey!" He shouted triumphantly, the manic grin slowly spreading across his face. "It glowed and there were voices and - how did Prisoner Zero escape, Pond?" He'd never called Amy 'Pond' before.

The ginger blinked at him. "He came through the cra-"

"I knew it!" Koschei said, jumping to his feet. "I knew I didn't just end up here and the time Lord's - they were having too much fun to send me back! I knew there had to be some other way for me to have ended up - but you mentioned the cracks were gone. How did I come through the cracks if the cracks are gone?" He slumped back down in his chair, arms crossed over his chest. The Doctor grinned at him.

"The universe can't go on without you in there somewhere," he muttered. Koschei glared at him. "Well, and the crack's probably showed up in a Time Lock of all things 'later' than they did for us."

The cheeky grin stayed on his face even as Koschei threw the large tome in his hands at him.