When you think you're safe, When you think you're all alone, That's when he'll come for you ... A silent killer stalks the city, targeting those home alone at night, playing a deadly game of cat and mouse with the victims. As panic spreads, Detective Inspector Helen Grace leads the investigation, but is herself a hunted woman, her every step shadowed by a ruthless psychopath bent on revenge. As she tracks the murderer, Grace begins to suspect there is a truly shocking home truth that connects these brutal crimes. But what she will find is something more twisted than she could ever suspect ...