Mine: The hot new thriller of 2018 - sinister, gripping and dark with a breathtaking twist

‘So now you use words to win and make money.’

‘I suppose so, yes. Does that sound selfish?’

Martin laughed. ‘You’re asking the wrong guy. I have “capitalist” tattooed across my chest.’

He looked at me, serious now. ‘But making money’s easy. I’m in awe of people like you who can find a tiny chink in the other guy’s armour to win a battle. I’m not sure I’d be mentally agile enough.’

‘I doubt that,’ I said.

I didn’t want to mention that I’d read almost everything I could get my hands on about Martin Joy. The general consensus in the dry trade papers that I had trawled was that he was a genius, one of the smartest financial minds of his generation. I loved the fact that he was so modest.

As we walked, we traded secrets about our lives. We discussed the box-sets we both wanted to watch but were too busy for, disclosed our favourite corners of the city – Postman’s Park in the City, the Roosevelt and Churchill bronze on Bond Street, the Bleeding Heart restaurant in Clerkenwell for its excellent red wine. I liked how easy it was to talk to him. I liked how much we had in common. He had once lived in Islington, just streets away from me in Highbury Fields, and although he had left for Spitalfields before I had even arrived, it gave me a secret thrill that our lives had once shared the same routine and rhythm.

‘Come on,’ I said, taking his hand and leading him down a side street, ‘I’m this way.’

He squeezed my fingers tighter and I lost all sense of everything going on around me, shrink-wrapped in our own little bubble.

For a moment I was reminded of my younger self, on the odd occasions I had met someone new and exciting. I was no different from the other young people looking for sex, love, leaving pubs and clubs with a boy, girl, suggesting dive bars or parties, wanting to stretch the night out longer, not wanting the spell to break.

But tonight I was very much an adult. Tonight we were heading straight home, and we both knew how the night would end.

‘Donna wants to meet me,’ said Martin suddenly. ‘Tuesday.’

My heart sank again, and I realized, right then, how much I liked this man. I didn’t want to feel needy, but I did – and it was Martin I needed.

‘Does she want to apologize for missing the First Directions?’ I said, glancing across.

‘I think she just wants to talk.’

‘Are you asking my opinion, or have you made up your mind to go?’

‘What do you think?’

My heart was beating fast now. I could feel the sword of Damocles hanging over me in the dark sky, like the black clouds that sometimes descended.

‘I think you should go,’ I said, knowing there was no other way to respond.

‘I thought so too,’ he said, gripping my hand tighter. ‘You said it’s better to try and stay out of the courts, right? It’s best to try and settle.’

‘Talk, yes, but don’t agree to anything.’

‘It’s only a conversation, Fran. I want to hear what she has to say. Without the lawyers around us. I just want to know what she’s thinking …’

He said it with a smile, but it felt like a reprimand. Without the lawyers around us. Without me.

‘How did it end, Martin?’ I asked, the words out of my mouth before I could stop them. ‘I mean, what actually happened?’

He looked at me, clearly weighing up whether it would be a good idea to tell me.

‘I went to Hong Kong,’ he said finally. ‘Business. I came back two days early and Donna wasn’t there. She’d just disappeared. That’s why I wasn’t surprised when she vanished this time. It’s Donna’s modus operandi. I finally tracked her down in New York, courtesy of the $47,000 credit-card bill. Hadn’t thought to tell me. She never thought about me. I wasn’t a person, a partner. I was just the provider,’ he said, his tone hard.

‘And you resented that?’

He shook his head. ‘Not then. By that time, I just didn’t miss her. I remember sitting in the house, in the dark, listening to the silence, and thinking how good it felt to be on my own, thinking this is how I want it to be.’

‘I’m on a date with a hermit,’ I laughed nervously.

He stopped, looked at me. ‘I’m just someone that wanted to get out of a marriage that had long passed its sell-by date. When she got back from New York, I told her I wanted a divorce.’

‘But she filed first,’ I noted. I knew the case file backwards. Knew that she had filed the divorce petition first.

‘She made sure she did that,’ he replied as if he was silently cursing himself for being slow off the mark.

‘And here we are,’ I said.

‘And here we are,’ he repeated.

The number 19 bus, my bus, stopped a few feet ahead of us, a flash of red, like a warning sign. A handful of people got off, buttoning their coats against the cold, and it hit me with a jolt that I recognized one of them. Pete.

Shit.

Instinctively, I let go of Martin’s hand.

‘Hello.’ Pete looked at Martin and then me.

‘Hi, Pete,’ I said politely, trying not to think of the last time I had seen him, when his lips had brushed against my neck. ‘Been out?’

‘Just popped to Ottolenghi.’

‘Popped, eh?’ he repeated, looking at Martin quizzically.

‘Oh, Martin – this is Pete Carroll, my neighbour.’

‘Martin Joy,’ he said, extending his hand. Pete kept his hand firmly in the warmth of his pocket.

‘Pete’s at Imperial. Doing a PhD,’ I said, trying to break the awkward mood.

‘Impressive,’ said Martin. ‘What in?’

‘Machine Intelligence.’

‘Oh, I work in fin-tech. We should talk when you finish.’

Martin hesitated for a moment. I thought he was going to produce a business card and was relieved when he didn’t. Perhaps Pete would forget his name, although I knew deep down I was fooling myself.

‘Well, I need some milk,’ said Pete, turning towards our local shop.

‘See you in the week,’ I said, as casually as I could.