Sir Derek O'Callaghan, the British Home Secretary, receives death threats before he goes into a nursing home for an operation. When he dies unexpectedly, his wife believes he has been murdered. Alleyn investigates the home where the cabinet minister died, and he finds things are indeed not as they should be, as at least two of the staff had a motive for killing their patient: a nurse O'Callaghan had taken advantage of and cast off, and the doctor who loved her. But was one of them responsible for the death threats, too?