General Heatherstone is a man haunted by a dark secret. Every year on the fifth of October, his fears intensify, and he becomes convinced that something sinister is about to happen. His paranoia has driven him to isolate his family from the outside world, but his children are growing restless and curious. When a young doctor, John Fothergill West, arrives at Cloomber Hall, he becomes entangled in the Heatherstone family's web of secrets and suspicions. As he investigates the strange events surrounding the family, West uncovers a chilling truth that will challenge his sanity and put his own life in danger.