After dinner he went for a walk on his own in the rain while Cecily made notes – for what purpose Hugh neither knew nor cared. He poked about in the ruins of the castle; he bought two tickets for the repertory theatre on the following night, hoping that the play, though it was called Murder-on-Sea, might distract Cecily; he wandered about the streets of the old town and he had a drink in the Oyster Catcher’s Arms. On the whole, he didn’t have a bad time.

The morning being better – a pale, sickly sun was shining and making quite attractive tints on the undersides of black clouds – he thought they might go on the beach. But Cecily had other plans. She got him to take her to Tarrington, and in the little shopping centre she left him to his own devices which included buying two pairs of thicker socks. After that, because it was raining again, there was nothing to do but sit in the car park. She kept him waiting two hours.

‘What d’you think?’ she said. ‘I found that chemist, the one that sold Rupert Moore the wasp killer that hadn’t got cyanide in it. And, would you believe it, it’s still the same firm. The original pharmacist’s grandson is the manager.’

‘I suppose,’ said Hugh, ‘that he told you his grandfather had made a deathbed confession he did give Moore the cyanide after all.’

‘Do try not to be so silly. I already knew they had cyanide wasp killer in the shop. It said so in the library book. This young man, the grandson, couldn’t tell me much, but he did say his grandfather had had a very pretty young girl assistant. How about that?’

‘I’ve noticed that very pretty young girls often do work in chemist’s shops.’

‘I’m glad you notice something, at any rate. However, she is not the one. The grandson knows her present whereabouts, and she is a Mrs Lewis. So I shall have to look elsewhere.’

‘What d’you mean, the one?’ said Hugh dismally.

‘My next task,’ said Cecily, taking no notice, ‘will be to hunt for persons in this case of the name of Jones. Young women, that is. I know where to begin now. Sooner or later I shall root out a girl who was an assistant in a chemist’s shop at the time and who married a Jones.’

‘What for?’

‘That right may be done,’ said Cecily solemnly. ‘That the truth may at last come out. I see it as my mission. You know I always have a mission, Hugh. It was the merest chance we happened to come to Northwold because Diana Richards recommended it. You wanted to go to Lloret de Mar. I feel it was meant we should come here because there was work for me to do. I am convinced Moore was guilty of this crime, but not alone in his guilt. He had a helper who, I believe, is alive at this moment. I’d like you to drive me to Clacton now. I shall begin by interviewing some of the oldest inhabitants.’