By confronting me with my diaries, Sykes had forced me to face the madness into which I’d fallen during my long years of isolation. I had buried Alice myself. I had even written of the event, so that I would never forget, but had then worked hard to do precisely the opposite. When I thought back to my imagined conversations with her, they seemed entirely real. I could still see her in my mind’s eye, standing there before me. But try as I might, I could no longer conjure her into even the illusion of objective existence. She remained a phantom, even as I curled up on the narrow bed they gave me, and I wept and cried out her name, filling myself with a grief too many years delayed.

That night, I remembered with desperate clarity my journey across a dying land to try and rescue her, only to find her dying. I remembered burying her in a shallow grave in the garden of the home we once shared. I remembered our honeymoon in Toulouse, where I had picked up a broken I Ching coin at a flea market, and joked we should each wear one half. And she, despite her derision, and her despisal of anything resembling sentimentality, had nonetheless followed my suggestion. I remembered taking her half of the coin, and pushing it into her cold and lifeless hand, before spading the dirt on top of her body.

I had failed to save her, as I had failed to save the human race. And then I had failed even to join the rest of my species in death. But at least now I knew that this place in which I found myself was, undeniably, real.

I was still, however, cuffed to the bed, and a guard had been posted outside my door, which remained open at all times. Every twenty minutes or so he would peer inside to see what I was up to.

The morning brought me a new visitor: a small, heavyset woman with short dark hair. She carried a tray loaded with coffee and toast in one hand and a plastic bag in the other. She waited as the guard uncuffed me, then she handed me my breakfast before introducing herself as Nadia Mirkowsky. There was an Eastern European lilt to her accent.

‘You want to know who we are, and why you’re here,’ she said. ‘In order to explain that, we’re going on a trip. But you need to promise you won’t pull any more stunts like last night.’

I rattled my chain. ‘You’ve been holding me prisoner without explanation. Why should I trust you?’

She inclined her head, as if acknowledging the point. ‘Personally, I think that was a mistake. But they had to make sure you were clear of the virus first, and we weren’t allowed in to talk to you.’

Who are ‘they’? I wondered. ‘Go on then.’