It’s 19 December 1931. Hercule Poirot and Inspector Edward Catchpool are called to investigate the murder of a man in the apparent safe haven of a Norfolk hospital ward. Catchpool’s mother, the irrepressible Cynthia, insists that Poirot stays in a crumbling mansion by the coast, so that they can all be together for the festive period while Poirot solves the case. Cynthia’s friend Arnold is soon to be admitted to that same hospital and his wife is convinced he will be the killer’s next victim, though she refuses to explain why.

Poirot has less than a week to solve the crime and prevent more murders, if he is to escape from this nightmare scenario and get home in time for Christmas. Meanwhile, someone else – someone utterly ruthless – also has ideas about what ought to happen to Hercule Poirot . . .