This is of course an oversimplification. My ingenious colleagues frequently think of many ways to outpace the puzzle, to give it relevance beyond the story, to suggest a universality of mystery. Many thrillers do not provide a solution – my own books often avoid the scene of final revelation where the plot is explicated. The displacement of the protagonist to a less involved character, the forensic pathologist and so on, has the same effect of distancing the writer and the reader from the superficial mystery. It opens other possibilities about the characters and the crime they have been caught up in, or a deeper interpretation of the world the characters live in, as well as other facts and the relevance of the clues.

Many readers say they enjoy the puzzle, though. There are clearly no answers to this.

I have prepared the ground because I knew we were moving towards some kind of final confrontation.

I had slept well overnight and I was up and alert. I was waiting for Jo to call me from Salay Ewwel to tell me she was boarding one of the inter-island shuttle flights. But earlier in the morning Spoder used the landline to tell me that Enver Jeksid had discovered my address, and that he wanted Spoder to come with him to the house straight away. I told Spoder that I would not be there, that I was meeting Jo at the airport. But it seemed inevitable that sooner or later the story of the Dearth police and their string of old murders was going to come to a head.

I braced myself for an anticlimax, but not eagerly.

Jo was one of the first passengers to appear through the arrivals gate. She was laden down. She was tugging a large wheeled case I had not seen before, as well as her usual travelling bags. I rushed to help her, and we stood hugging for a long time.

In the car she talked excitedly of what she had done and achieved, the people she met, the project she was working on, the future plans.

‘Does this mean you will have to take more trips to Muriseay?’ I said.

‘Only occasionally. No more long visits, anyway. I’ll be submitting my designs online. It’s all worked out. We’ve shared software, and they’ve set up a protected internet page where we can discuss ideas. I’ll probably have to go back to the theatre for dress and technical rehearsals, and the opening, but mostly I’ll be working from home. When I go next time, you could come with me?’