Elderly Martha Beckett is a prisoner in her own home, and has been ever since her older brother disappeared at just nine years old. He went to hide in the cellar and never came back. And now Martha has sworn to protect anyone else from the evils lurking just below her floorboards. But whatever it is, has woken up-- and is hungry again. When she calls the police for help, Annie Graham is the first to respond. Now Annie Ashworth, she is happily married to fellow police officer Will, with a gorgeous home and a job she loves. But then she hears the news--serial killer Henry Smith has escaped from his mental hospital and is on the run. So when a severed head lands at her colleague Jake's feet--they can only assume that Henry is back to his old tricks.