In the shadowy woods of summer camp, Kim's world is shattered when her quirky, unpredictable camper, Sarah, attacks her under a full moon. ​Surviving the mauling against all odds was just the beginning. Something has changed deep within Kim. ​Back home in the rugged mountain town of Alden, Colorado, Kim grapples with raging new senses, a fractured family, and a high school full of plastic smiles. But a deeper rot is festering in Alden. Something ancient and evil has arrived, a creature that wears her classmates' faces and feeds on their agony. ​To survive, Kim must unravel the mystery of the monster stalking the hallways while fighting to control the predator growing inside her. With the help of an unlikely group of outsiders, she is racing against a ticking clock to find the beast's heart before the next full moon-and before the monster in her, or the one in her school, consumes everything she loves. ​Will Kim be able to stop the horror without, or will she lose herself to the hunger within?