In the closing months of the Second World War Albert Campion returns from a secret mission which has kept him overseas for three years. He visits his London home and plans to have a bath before catching a train out of the city that evening. Whilst he's bathing, his manservant, Lugg and an aristocratic lady carry a woman's body into his bedroom. Campion would prefer not to become involved - he has a train to catch after all - but he's prevented from leaving the city and has to apply himself to solving the mystery of the woman's death and of the disappearing art treasures.