A young woman wakes up in a cold, dark cellar with no idea how she got there or who her kidnapper is. So begins her terrible nightmare. Nearby, the body of another young woman is discovered buried on a remote beach. But the dead girl was never reported missing, her estranged family having received regular texts from her over the years. Someone has been keeping her alive from beyond the grave. For Detective Inspector Helen Grace it's chilling evidence that she's searching for a monster who is not just twisted but also clever and resourceful -- a predator who's killed before. And as Helen struggles to understand the killer's motivation, she begins to realize that she's in a desperate race against time.