‘I had to explain that, given my nickname, dictating The Modification was as if I were God, handing down the Ten Commandments to Moses. I meant it as a joke. But they took it seriously. They started to refer to the plan as the Modification Commandments.’ He clicked his tongue. ‘I feel sorry for those who don’t appreciate irony. But to get back to the issue: how you found out about me … If you’re willing to share.’

‘Of course.’

‘You had the notebook. But it wasn’t in my handwriting; that was Billy’s. No fingerprints or DNA. I never touched it. And, yes, there were a lot of references to critical timing – when to administer the poison and where, the diversionary attacks, when to have Joshua, Billy’s cousin, get the batteries and lights in the underground passages where the crimes occurred, how many minutes after someone had called nine one one could the police be counted on to arrive. It’s all in the timing, of course. But leaping from that to my escape from prison?’

Rhyme wondered where the man was standing, what his posture was. Was he outside, cold? Or outside, hot, in balmy weather? ‘Nemesis’ was an imprecise term, not to mention melodramatic. But Rhyme allowed himself to think of the Watchmaker this way. He said, ‘Evidence.’

‘That doesn’t surprise me, Lincoln. But what?’

‘The tetrodotoxin. We found traces.’ The super poison from the fugu fish.

‘Oh, my …’ A sigh from the other end of the line. ‘I told Billy to destroy any residue.’

‘I’m sure he tried. There was just a minuscule amount of trace at one of the scenes.’ Rhyme, of all people, knew how difficult it was to banish all whispers of a substance. ‘We didn’t find any in his safe house, so where had it come from? I checked VICAP and nobody had used it in any crimes that had been reported in the last few years. So what could Billy have been doing with tetrodotoxin? Then it occurred to me: A clue was its nickname, the zombie drug. To induce the appearance of cardiac arrest and death.’

‘That’s right,’ the Watchmaker admitted. ‘Billy delivered some, smuggled in the pages of a book. In prison they check for shivs and heroin, not milligrams of fish ovary. I used it to fake the heart attack and get transferred to the hospital in White Plains.’

Was that a seagull cawing in the background? And then, a ship’s horn? No, a foghorn. Interesting. They were little used in this day of radar and GPS. Rhyme took note. A flare on his computer screen. It was a message from Rodney Szarnek, the computer crimes expert. It reported that the analysis of the Watchmaker’s call to Rhyme had been unsuccessful; it had skidded to a stop at an anonymous proxy switch in Kazakhstan.

Rhyme had lied about the phone trace.