When Inspector Thomas Daykin is transferred to Harrogate, he is told that his first case will be very simple: a local businessman, grieving for his wife, has committed suicide. However, as Daykin begins to look into the case, he discovers that things are not quite as they seem. The suicidal businessman has been poisoned and one of his acquaintances has mysteriously drowned. When it emerges that both men belonged to a club whose members are being murdered one by one, Daykin realises that he must act swiftly. If he is to save the remaining three men, he must first find out who wants them dead, and why.