Martin Caldwell? What did he want? They barely knew each other. He was a friend of Caro’s from student days. And of April’s. They’d shared a house in Exeter with several other students during their last year at the university. He’d come to Caro’s funeral and Nick recalled meeting him a few times before that, spread over a lot of years. They’d exchanged a few words during the wake. But there’d been nothing to suggest Nick would ever hear from him again.

‘You’re probably wondering why I’m phoning you … out of the blue … like this.’

Nick was wondering exactly that. Caldwell’s voice – soft, hesitant, unassertive – summoned for Nick a clear memory of his appearance at the funeral. Lean and hunched, with a narrow face and grey hair worn too long, he was one of the few mourners who’d opted for black suit and tie, even though the suit didn’t fit properly. He’d kept saying he couldn’t believe Caro was dead. ‘She was always so alive.’ After a short while, Nick began to find him annoying and slipped away, leaving Caldwell … alone. Was that it, perhaps? Was he simply lonely?

‘It took me a long time to find your number. I jotted it down after … you called me … about Caro’s funeral.’

Nick had forgotten doing that. But he’d phoned quite a lot of people at the time, to take some of the load off April. He had no recollection of their conversation. There was no reason why he should.

‘The thing is, something … rather surprising … has happened. And it, well, it’s … something I think you need to know about. I mean … really need to know about.’

It was hard, if not impossible, to imagine what he could possibly be talking about. Nick waited, wondering if Caldwell was actually going to say what it was in the message.

‘Could you phone me back as soon as possible, please? It’s really … well, rather urgent. I’m going to be in London early next week. Could we, er … meet? I, er … seriously think we should. Give me a call … when you get this.’ He recited his number.

Nick didn’t think Caldwell lived in London. He seemed to recall someone saying, perhaps Caldwell himself, that he’d never actually left Exeter after university and had spent his working life in the city. And Nick had been told something else about where Caldwell lived that lay just out of his memory’s reach.

‘Leave a message if I don’t answer and I’ll get back to you as soon as I can. I’ll, er … look forward to hearing from you.’