Just returned from years overseas on a secret mission, private detective Albert Campion is relaxing in his bath when his servant Lugg and a lady of unmistakably aristocratic bearing appear in his flat carrying the corpse of a woman. At first Campion is unwilling to get involved, but he is forced to bring his powers of protection to bear on the case, and to solve not only the mystery of the murdered woman but also the alarming disappearance of some well-known art treasures.