Clifford Flush had not murdered anybody for years. But when he felt the urge to kill his bridge partner he was blackmailed into leaving London. He and his fellow Asterisk Club members, all of whom had been wrongfully acquitted of at least one murder, establish themselves as professional homicide consultants in the ugliest manor house in Dorset. After all, if they could commit the perfect murder why not share that knowledge with the world - for a handsome fee?

Flush conducts classes on Grips, Knots, Electricity, Court Etiquette and Alibis. Mrs Barratt teaches Anatomy and Forensic Medicine. Colonel Quincey specialises in Automobiles and Firearms. Everything is going just fine until a member of the 26th class has the effrontery to get himself murdered on the premises.