Our days lasted between 15 and 18 hours, with random variations. [...] That was how we established that we were living according to an artificial clock. We needed to understand why.

Emma put forward the craziest theory.

'We're not on earth. We are on a planet that rotates every 16 and a half hours.'

'How would we have got here? How did we get into the bunker?' I asked.

Nobody had the least idea, which amazed me.

I'd put my own lack of memories down to the fact that I'd been so young and to the women's state of a shock that Anthea had described to me, but the others knew no more than I did. Apparently, life had been going on as usual, when suddenly, in the middle of a night that had begun like any other, there'd been screams, flames, a stampede, things which I, who'd always lived in the quiet of the bunker, couldn't begin to imagine. [...]

'The fact is that none of us seems to have any coherent memories that would enable us to piece together what happened. We don't even know if there was a war,' said Dorothy. 'I can recall only vague images: I see flames, people running in all directions, and I think I'm tied up and frightened. It goes on for a very long time. I'm still frightened, but there aren't even any images any more.'