The warden of the Plas Mawr Adventure Centre, Charles Martin, is a weak man whose unfaithful wife, Bett, has driven him to drink. Then Bett is found dead in her husband’s crashed Jaguar, at the foot of a cliff. At first, it is assumed to be an accident or suicide, but further developments show that it is a murder case. Tough, middle-aged Miss Pink, one of the Centre’s directors, proves herself to be a shrewd amateur detective. She puts two and two together and realises that the Centre is being used as a cover for something very serious.