Made-for-TV crime thriller based on the novel by Agatha Christie. The murder of influential millionaire George Barton (Kenneth Cranham)'s wife at a plush dinner party is the mystery at the heart of the feature. Who was responsible for committing the crime? Colonel Geoffrey Reece (Oliver Ford Davies) and Dr. Catherine Kendall (Pauline Collins) head the investigation, which looks set to lead to the very top with the discovery that the victim was having an affair with a high ranking government minister.