The police called Claire because a girl matching Jane’s description had been seen at King’s Cross station. They couldn’t tell if she was alone – she was surrounded by commuters – but they were confident that she had walked through the station concourse. They were checking CCTV to confirm that she hadn’t boarded a train.

Jameson knew there was nothing he could do but wait and so he set off on a bike ride. The cortisol was making him jumpy and irritable. If he wanted to pass himself off as an authentic psychopath, he needed to know how they operated, what they thought and what they felt. Bloom had recommended Robert Hare’s Without Conscience, a study of psychopaths from the man who invented a way to identify them, Confessions of a Sociopath by M. E. Thomas, an autobiographical insight into life as a sociopath by an American lawyer, and The Wisdom of Psychopaths by Oxford University’s Professor of Psychology, Kevin Dutton. Jameson parked his bike and downloaded Confessions of a Sociopath to his phone.

Two hours and fifty pages later, he arrived home. There was no more news about Jane. What the hell had she been doing at King’s Cross? The police had tried to trace her phone, but it was switched off. He had a bad feeling. Jane wasn’t the type to play truant. She was responsible. Running away simply didn’t make sense.

After taking a shower, Jameson headed into town to meet Sarah. He’d been tempted to call it off – he wasn’t sure he’d be good company – but in the end he’d decided to go. It had been a long time since he’d wanted to see a woman as much as he wanted to see Sarah, and he’d just be sitting at home waiting for news, so why not sit with her? It might take his mind off things.

On the tube, he reflected on the first few chapters of Confessions of a Sociopath. He wasn’t entirely sure how he felt about it. The author, a self-confessed sociopath, was articulate, intelligent and, on occasion, witty. But there was an underlying tone of frickin’ scariness. There was something so removed about how she viewed the world and other people, as though they were pawns in an elaborate game of chess.

Jameson stepped out into the chilly March sunshine and headed towards Fork. They were meeting there and then heading to a nearby pub. As he turned the corner and Fork came into view, he saw Sarah waiting for him. She was wearing a tailored white coat with black knee-high boots. Her hair was long and straight, stretching halfway down her back. She looked his way and smiled. He’d made the right decision. She was bound to cheer him up; he’d feel much better in a few hours.

But she never had the chance.