I thought, then, of Herschel Nussbaum, and his partner-in-genocide, Marlon Keene, both dead by my own hand. They had not been working alone.

I stood quickly, and cast a wild glance towards the poplars and the deeper woods spreading down the far slope of the hill, wondering just who might be looking back. The trees and the rusting turbines took on a menacing quality they’d never had before. I had dreamed of an improbable rescue for years, and yet I had good reason to be very afraid of being found.

My shotgun. It was still propped against the wall of the shed. I ran back in to retrieve it, but my hands were shaking so hard I fumbled with it at first.

I stepped back outside and saw Alice standing staring down at the bootprints. Her feet, I saw, were clad in cheap trainers, rather than boots.

‘Where the hell were you?’ I demanded, the strain evident in my voice. ‘Stay where I can see you!’

When she looked up at me, her face was shining. ‘Someone’s found us,’ she said, her tone full of astonishment. ‘Oh, my God, Jerry! Do you know what this means? Someone’s come to rescue us—’

‘Then why were they wandering around here in the middle of the night instead of coming down to the goddam house?’ I demanded. ‘How long have they been out here, watching us?’

Alice frowned at me, pulling her cardigan closer around her narrow shoulders. ‘What are you so worried about? I—’

‘Don’t you understand?’ I nearly yelled at her. ‘Who could they be, but Red Harvest? Who else could have the antidote? Who else could still be alive after they poisoned the entire bloody planet? Don’t you see? Maybe they want revenge, for what I did to Nussbaum and Keene!’

‘You’re being ridiculous,’ she scoffed. ‘They’re all just as dead as everyone else; you know that. You found their base and they were all—’

I had travelled to the States a few years after the apocalypse. It had taken me nearly two years to get there, where I could once have flown to my destination in a matter of hours. Red Harvest’s main compound and centre of operations had turned out to be deserted, bar a few hundred corpses scattered through dormitories and basement rooms.

‘No,’ I said, shaking my head. ‘I can’t be sure. Not really sure. Some of them could still be alive, if they had the antidote.’

Focus. I took a deep breath, fighting off panic. I examined the bootprints again, studying the path they took. All three sets, I saw, encircled the nearest turbine. One of them had stepped away, the grass flattened where they had approached the first of the fence posts that supported the power cables extending towards my house.