So you do know about his infatuation, Molly thought, but you indulge him in it, as you indulge him in everything else.

“How did you meet him?” she asked, too curious to be concerned by the impudence of asking.

“I was matron of a rest home for the elderly,” she said. “A small, private home, my own business. His mother was one of our residents. He visited her regularly. When she passed away, he asked me to marry him.”

That’s it, Molly thought, identifying at last the nature of the relationship between Paul and Marjory Derbyshire. She treats him, not like a child, but like a very old, slightly demented gentleman whose fantasies must be humoured and who must be protected from his own mischief.

Paul Derbyshire had taken George Palmer-Jones into a small room. It must, George thought, be very similar to his surgery. There was a desk with a card index, and on the walls rows of books. Half of them were medical, academic, half of them concerned with natural history. A large, glossy book lay on a sheet of brown paper on the desk. They discussed it briefly.

George did not want to frighten the doctor into immediate denial.

“I believe that Charlie had something which belonged to you, when he died,” George said carefully.

“How do you know?”

“I don’t wish to tell you that. I want to know how it was returned to you.”

But Paul Derbyshire did not answer the question.

“Did he talk about it to anyone?” he said wildly. “How could he understand? He never cared for anyone but himself. Well, it’s too late. I’ve burnt it. No one can prove anything now.”

George tried not to show, not to feel, distaste. “I don’t think,” he said, “that it’s a matter of proving anything. But I need to know how it was returned to you. I do not wish to involve the police.”

Again the doctor reacted irrationally. “Tell the police. No one can touch me now. It is burnt, and Charlie is dead.” He grew more calm. “Besides,” he said sadly, looking up at George through the straight shank of white hair which had fallen over his forehead, “nothing ever happened, you know. Nothing ever happened.”

It had been a strange conversation. There had been no direct questions, no proper answers, but George thought that they had understood each other. He understood, at least, that Paul Derbyshire would talk no more about it. He stood up.

“I would like everyone to be on the island the day after tomorrow. Will you come?”

It was as if the previous exchange between them had never happened.

“Yes,” the doctor said. “Give me the details, and I’ll come.”

Elizabeth was waiting for them in the Land Rover. She was reading a library book. There was an empty sandwich box on the seat beside her. It seemed that she had been there for some time. All three of them sat in the front, squeezed together in relative comfort. She drove down the slipway on to the sand. The sun was very low in the sky. They drove directly towards it. The island was a silhouette suspended between sky and shore. Elizabeth spoke for the first time.