On a spring morning in 1951, eleven-year-old chemist and aspiring detective Flavia de Luce gathers with her family at the railway station, awaiting the return of her long-lost mother Harriet. Yet upon the train's arrival in the English village of Bishop's Lacey, Flavia is approached by a tall stranger who whispers a cryptic message into her ear. Moments later, he is dead, mysteriously pushed under the train by someone in the crowd. Who was this man, what did his words mean, and why were they intended for Flavia? Back home at Buckshaw, the de Luces' crumbling estate, Flavia puts her sleuthing skills to the test.