Twenty-fifth in the long-running mystery series with Dr Launcelot Priestley.

Every year, for a month or so, a crowd descended on the village of Culverden every weekend. They came primarily from the poverty-stricken East End of London, to visit the countryside and to make a bit of money picking hops. They stayed in huts away from the village dwellers, drank outside the pub rather than inside – unwelcome in some ways but a vital part of the economy nonetheless.

Then one night Sergeant Wragge happened to see something unusual lying by the side of the road, and decided to take care of it himself. After all, a twelve-inch butcher knife is nothing to be left loose on a public highway. When he noticed those curious stains on the blade, his suspicions were more than aroused and he felt that he must be ready for trouble.

The Sergeant’s forebodings were swiftly corroborated by the events that followed - robbery, a mysterious disappearance, perhaps murder; so he felt that he was justified in demanding the aid of Scotland Yard. The careful investigations of Inspector Hanslet and Jimmy Waghorn soon had them on the right track; but it was Dr. Priestley’s quiet, seemingly enigmatic suggestion that finally unearthed the solution.