"Howe is a formidable researcher and writer, and this creepy, gripping novel is intimately layered, shedding light on the challenges teenage girls have faced throughout history."-The New York Times Book Review A chilling mystery based on true events, from New York Times bestselling author of The Physick Book of Deliverance Dane. It's senior year at St. Joan's Academy, and school is a pressure cooker. College applications, the battle for valedictorian, deciphering boys' texts: Through it all, Colleen Rowley and her friends are expected to keep it together. Until they can't. First it's the school's queen bee, Clara Rutherford, who suddenly falls into uncontrollable tics in the middle of class. Her mystery illness quickly spreads to her closest clique of friends, then more students and symptoms follow: seizures, hair loss, violent coughing fits. St. Joan's buzzes with rumor; rumor blossoms into full-blown panic. Soon the media descends on Danvers, Massachusetts, as everyone scrambles to find something, or ...