The first entries were as I remembered them: identical to my own. It was strange how quickly the memories came back of what now seemed another life, and I found myself remembering also how it had all started, and how I came to be alone in the world for so many years.

If it hadn’t been for an old college friend, I might never have survived the end of the world.

Not long after graduation I had got myself hired by a research outfit named GreenTech based in San José, on the strength of my PhD thesis on experimental biogenetics. GreenTech liked the predictive computer models I’d developed to help in combating antiviral-resistant diseases. Then, over the course of my first year working for them, I gradually became aware that GreenTech had a number of research contracts with the US military.

Now, this was far from unusual, even in biotech, and the money that kind of work could bring in often made the difference between life and death for companies like GreenTech. I never had cause to think any more of it, until the day I got an email from Floyd Addison, an old friend from university, saying he was passing through town and asking me to meet him for lunch.

As it turned out, however, Floyd was doing anything but ‘just passing through’.

We met at a diner a short walk from my work. I was still unused to the dry air and heat of California, after years of studying in Britain and dealing with its blustery rain and four-seasons-in-a-day weather. We talked about old friends, and about my recent wedding to Alice Crosby, and he apologized for not being able to make the wedding. We made small talk about buying vs renting, and the shocking rental prices in San José. I only realized that this was more than just an unexpected social call when he dropped a fat manila folder on the table between us.

‘Have you ever heard of Red Harvest?’ Floyd asked me, eyeing me speculatively.

‘I don’t think so.’ I glanced uncertainly down at the folder and wondered what was going on. ‘What is this?’

Floyd responded by pulling some photographs out of the folder. ‘Know any of these people?’

I gave him an appraising look, then glanced through the photographs, feeling as if I’d just stumbled into some ridiculous spy movie. ‘Sure,’ I said warily. ‘That’s Marlon Keene, the other one is Herschel Nussbaum. They’re colleagues at GreenTech.’ I laughed uneasily. ‘What are you these days, some kind of spook?’

‘Red Harvest is a religious group,’ said Floyd. His Oxford education had smoothed out the rougher edges of his Kentucky accent. ‘A cult, by any other name, and one with strongly millennialist leanings.’

‘What does that even mean?’

Floyd’s eyebrows rose by a couple of millimetres. ‘It means,’ he said, ‘that they’d really like to bring about the end of the world.’