In the 1920s, Lady Constance de Momery presides over a costume ball for her grandson, but all is not as it seems and when young heir to the estate Felix de Momery announces his engagement to sweetheart Ruth, his friends Billy and Katherine seem far from pleased.

Back in the present day, commitment-shy Ben begins to discover that, though demolished, Geap Manor casts a long shadow. Having recently left his girlfriend Hannah for a life of excitement over cosy domesticity, he is excited by the curator's stories and screws the ancient door knocker to his new front door. However, he soon finds himself getting more excitement than he bargained for as the past begins to intrude rudely with a loud knock at the door in the night and a terrifying journey into Geap Manor's bloody past.