Detective Scobie Malone accepts a mission to fly to London to arrest Sir James Quentin, a high-level commissioner wanted down under for murder. But when Malone arrives, he finds that the amiable Quentin is not only the key in groundbreaking peace negotiations, but also the target of an assassin himself.

Sydney homicide detective Sergeant Scobie Malone and his offsider investigate the murder of Helga, whose corpse is found in the basement of the Sydney Opera House.