"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...

A deadly, mysterious epidemic is sweeping the country, and young kidnap victim Callie is one of the few who survived infection, only to be sacrificed by her captors at a secret lab working with antimatter; her older brother Kai is desperate to find out what happened to her--his best hope lies with Shay, the girl who last saw Callie alive, and together they will seek answers, even if it means evading soldiers and crossing the quarantine zone.