I shook my head. ‘The thing that gets me,’ I said, ‘is all those bunkers filled with bodies.’ Several unearthed by previous exploration teams had found nothing but corpses dead from starvation, disease, radiation poisoning, suicide, or some combination of all of the above. This, I had learned, was typical, here or on any other alternate. ‘What’s the point of building a bunch of damn bunkers if everybody using them still winds up dead?’

‘Bunkers, in my experience,’ said Haden with a grin, ‘are hugely overrated.’

‘You’re on a mission with Haden?’ Yuichi had chuckled the day before, when I ran into him outside the commissary. ‘Now there’s a weird one.’

‘Everybody’s been saying that ever since I came out of quarantine, but nobody’s bothered to explain it to me yet.’

‘Really?’ He looked surprised. ‘Well, for one thing, nobody knows just what happened to the alternate they found him on. It’s intact. There’s no sign or evidence of violence, of unrest, of anything at all, really. It’s like everyone just got up one day and disappeared.’

It occurred to me that much the same could be said for the island in whose empty homes we lived, but decided not to mention that. ‘So what does he say happened?’

Yuichi shrugged. ‘He ain’t got much of an explanation himself, either,’ he replied. ‘Claims to have total amnesia. They worked him over with truth drugs, hypnosis, everything, so I hear.’ He shook his head. ‘Couldn’t find nothing out. And then there’s the . . . you know.’ He glanced around before gesturing at his eyes.

‘Are you sure he’s not maybe just wearing contacts of some kind?’

‘Very sure. He got worked over by the doctors at the base compound.’

I shook my head and chuckled. ‘So maybe he’s an alien.’

Yuichi looked alarmed. ‘Don’t ever say that around Casey or Wallace. The pair of them are total conspiracy nuts. They love all that shit.’

‘All right,’ I said, ‘what’s your opinion of him?’

‘Who cares? The universe is full of mysteries. I like it that way. Makes life more interesting, don’t you think?’

‘There we go,’ said Haden, after some hours of flight. ‘Destination in sight.’

I woke with a start, unaware I had fallen asleep. Brightly coloured controls hovered beneath Haden’s fingertips, spun out of light. The aircraft had begun to angle downwards on its final approach.

I mumbled something and blinked sleep out of my eyes before looking out and down at Salt Lake City’s empty streets. Our destination was the University of Utah’s seismic research lab, from which we were required to retrieve data regarding the Yellowstone eruption.

‘Don’t you ever wonder what the point of all this is?’ I asked. The plane dipped down more, and Haden leaned back, dismissing the controls. I tried not to show how nervous that made me.