It was physically impossible for Sir George or Jim Warburton to have killed Marlene Tucker. Since it was not physically impossible for Mrs Oliver to have done so, he added her name after a brief space. He also added the name of Mrs Masterton since he did not remember of his own knowledge having seen Mrs Masterton constantly on the lawn between four o’clock and quarter to five. He added the name of Henden, the butler; more, perhaps, because a sinister butler had figured in Mrs Oliver’s Murder Hunt than because he had really any suspicions of the dark-haired artist with the gong stick. He also put down ‘Boy in turtle shirt’ with a query mark after it. Then he smiled, shook his head, took a pin from the lapel of his jacket, shut his eyes and stabbed with it. It was as good a way as any other, he thought.

He was justifiably annoyed when the pin proved to have transfixed the last entry.

‘I am an imbecile,’ said Hercule Poirot. ‘What has a boy in a turtle shirt to do with this?’

But he also realized he must have had some reason for including this enigmatic character in his list. He recalled again the day he had sat in the Folly, and the surprise on the boy’s face at seeing him there. Not a very pleasant face, despite the youthful good looks. An arrogant ruthless face. The young man had come there for some purpose. He had come to meet someone, and it followed that that someone was a person whom he could not meet, or did not wish to meet, in the ordinary way. It was a meeting, in fact, to which attention must not be called. A guilty meeting. Something to do with the murder?

Poirot pursued his reflections. A boy who was staying at the Youth Hostel – that is to say, a boy who would be in that neighbourhood for two nights at most. Had he come there casually? One of the many young students visiting Britain? Or had he come there for a special purpose, to meet some special person? There could have been what seemed a casual encounter on the day of the fête – possibly there had been.

I know a good deal, said Hercule Poirot to himself. I have in my hands many, many pieces of this jigsaw. I have an idea of the kind of crime this was – but it must be that I am not looking at it the right way.

He turned a page of his notebook, and wrote:

Did Lady Stubbs ask Miss Brewis to take tea to Marlene? If not, why does Miss Brewis say that she did?