The American writer, Kenneth Magee (played by Desi Arnaz Jr.), arrives at the manor house, known as Ravenshurst, and finds it to be a creepy and isolated place. He is greeted by the housekeeper, Mrs. Ketchin (Sheila Keith), who seems to know more than she is letting on.
As he settles in, Magee meets the manor's owner, Lionel Grisbane (Vincent Price), who is a creepy and eccentric actor. Grisbane has summoned four other famous writers to the house, including John Kendrick Bangs (John Carradine), Sebastian Grisbane (Christopher Lee), Corrigan (Peter Cushing), and Denise Royle (Julie Peasgood), all of whom seem to have their own hidden agendas.
As the writers all prepare to write their individual works of fiction, strange things begin to happen in the house. The group discovers that the house is occupied by a family of four, the Smiths, who have been locked away in the attic for years. They also learn that the manor has a dark and violent past.
As the night wears on, the writers become increasingly paranoid and mistrustful of one another, and they try to uncover the secrets of the house before it's too late. The eerie atmosphere of Ravenshurst and the tension between the writers creates a suspenseful and unsettling tale.
In the end, Magee manages to complete his novel and win the bet, but the shocking revelations about the manor and its inhabitants leave him and the other writers forever changed. House of the Long Shadows is a suspenseful and atmospheric horror film that features a talented cast of veteran actors in a classic haunted house setting.