1867. Eliza Caine arrives in Norfolk to take up her position as governess at Gaudlin Hall on a dark and chilling night. As she makes her way across the station platform, a pair of invisible hands push her from behind into the path of an approaching train. She is only saved by the vigilance of a passing doctor. When she finally arrives, shaken, at the hall she is greeted by the two children in her care, Isabella and Eustace. There are no parents, no adults at all, and no one to represent her mysterious employer. The children offer no explanation. Later that night in her room, a second terrifying experience further reinforces the sense that something is very wrong. From the moment she rises the following morning, her every step seems dogged by a malign presence which lives within Gaudlin's walls. Eliza realizes that if she and the children are to survive its violent attentions, she must first uncover the hall's long-buried secrets and confront the demons of its past.
