At the Convent of St Mary Magdalene, an ex-army corporal, Billings, breaks into the chapel and steals a priceless silver chalice. As Billings is escaping he is killed by Dieter Krantz, a dealer in stolen art, who takes the chalice and hides the body.

Acting on a tip off that the Stern gang have a cache of arms ready for shipment, the police raid a house in South London. No arms are found but Sir Derek O'Callaghan's name is found. Sir Derek O'Callaghan, a prominent Cabinet Minister, has been receiving letters threatening his life and is facing a censure motion in the House because of his handling of the Palestine situation.

October 1948 and Chief Inspector Alley returns from an overseas trip collecting a con-man Trumper - to find Agatha Troy has a strange story to tell him.

Eminent barrister Luke Watchman and his friends stay in a rambling Inn for their annual holiday. While the guests gather in the bar, owner Abel is putting cyanide in a rat hole in the garage.

Mrs Dorothy Halcut-Hackett, society beauty and wife of General Halcut-Hackett is being blackmailed. The police have set a trap for the blackmailer. Another letter arrives giving a new date and location.

The first episode of the popular crime series featuring Ngaio Marsh's aristocratic detective. Alleyn investigates the murder of a model at a summer school.