A man is found dead in a hotel in the countryside. The police are engaged in their own investigation, but in parallel, Miles Breedon and his wife, on behalf of the insurance company with which the deceased was insured, are conducting their own investigation. Miles is going to prove that this is a suicide, which seems to be indicated by the position of the gas taps in the murdered man's room. Miles's old friend, Police Inspector Leyland, is convinced that this is murder - and so a bet is born, the result of which will be an inventive and surprising explanation for the mysterious death.