A storm rages outside Casey's cabin, but it's the girl at her window that truly unnerves her. Young, alone, and wielding a knife, the girl refuses to explain her presence or release her grip on the weapon. As Casey investigates further, she uncovers a dark secret that the girl will kill to protect. In this tense psychological thriller, Freida McFadden delves into the lengths one girl will go to survive and the deadly consequences of her actions.