From Natalie D. Richards, the New York Times bestselling author of mystery books for teens, comes a pulse-pounding thriller about two teens who uncover something sinister, perfect for fans of Natasha Preston and Karen McManus. Mallory didn't want to leave home, but it wasn't safe to stay. So she sleeps at her best friend's house and spends the rest of her time at the library, doing her online schoolwork and figuring out what...