A revolution erupts in the small Middle Eastern state of Ramat, and in the chaos a fortune in jewels is spirited out of the palace by people who will not survive to deliver it. The stones vanish, but their trail leads, improbably, to England and to Meadowbank, an exclusive school for girls run with quiet authority by the formidable Miss Bulstrode. A new term begins with fresh staff, a foreign princess among the pupils, and the ordinary frictions of school life. Then a games mistress is found shot dead in the new Sports Pavilion late at night, and the careful order of the place begins to crack. As fear spreads through the dormitories and common rooms, more violence follows, and parents start to withdraw their daughters. Suspicion settles on the recently hired teachers, each carrying secrets that do not quite fit the genteel surface. One observant schoolgirl, refusing to wait for the adults to act, makes a discovery and decides to seek out Hercule Poirot, who enters the affair well after events are already in motion. He must untangle a knot that links international intrigue, smuggled treasure, and personal ambition, deciding which of the strangers gathered at Meadowbank has been hiding in plain sight. The result is a mystery that begins far from its English setting and steadily draws every thread back to a single quiet schoolroom.