“Put it on the board,” Ella would say if she heard them talking about the birds they had seen. The board was an old school blackboard, salvaged when one of the nearby village schools had closed. It was covered each day with records of birds seen in the area and rare birds seen elsewhere, with witticisms and juvenile jokes and rude pictures of birdwatchers. It was the means by which information was transferred. Each evening Ella would edit it, with a duster, censoring any items of which she disapproved, giggling despite herself.

So when George arrived at the Windmill after his visit to Sally’s, Molly was still sitting at the counter, comfortable, unobtrusive. He felt a pang of guilt and gratitude, because he had known that she would still be there, because she was so reliable. He smiled at her and she smiled back to tell him that she did not mind, that in fact she had been quite enjoying herself.

“Is there anything about, Ella?” he asked, just as all the other birders had done.

“I don’t think that there’s anything special. But look on the board!” This last phrase was shouted in the tone of exasperation a mother uses when reminding a child to close a door.

Obediently he read the board while she made him sausage and chips and tea. There were a couple of bluethroats at Wells, a golden oriole on Salthouse Heath, good birds, but nothing special enough to bring a group of experienced birdwatchers back from Scotland before the weekend was over. They needed a real rarity. He had an idea.

They walked from the Windmill out on to the marsh. George took Molly’s hand and described his visits to the remand centre and to Sally’s home.

“So that’s why she always felt so obliged to Tom,” Molly said. “It must have been horrible.”

“It can’t have been easy, being in debt to Tom,” George agreed. He continued carefully: “ I’m beginning to develop an idea about what might have happened to Tom. My discussion with Sally helped to confirm it.” Tentatively he explained his feelings about the case. “Do you think that it could have happened that way?”

“I think you’re right,” she said after a pause. “I don’t like it, but I think that you’re right. Why do you want to look at the marsh again?”

“Because I haven’t properly considered the practical details of my theory. It didn’t occur to me, until I drove back from Fenquay, where Tom might have been killed. It’s too late to tell if I’m right. There will be no sign left now. But we can check if my murderer could have moved the body to the pool. If it just isn’t practically possible, I’ll have to think again. I want to find Terry’s short cut into the White Lodge.”

The marsh pool was closer to the track than George had remembered, and the body had been found in the water nearest to the track. There was a narrow sandy footpath from the track to the pond.