In the old English manor of Buckshaw, the last representatives of an aristocratic line live—an eccentric Colonel de Luc and his three daughters.
In the summer of 1950, the languid swamp of rural life is disrupted by incredible events: the murder of a stranger and the arrest of the colonel. While the older daughters, as proper well-bred English ladies, cry into their handkerchiefs, the youngest, eleven-year-old Flavia, is thrilled: at last something has happened in her life! Her analytical mind, passion for chemistry, and especially for poisons will help her sort out this puzzling case, on which the local police have already broken their teeth.
Flavia begins to search—searches that will lead her, nothing less, directly to the King of England himself. She is sure of one thing: her father is innocent—on the contrary, he protects his daughters from something terrible…