Upon finding an old tome of the occult in their newly acquired house, Donald Capel’s wife, Wendy, becomes possessed by a malevolent spirit, bringing her close to death. In an attempt to save her, Donald’s niece initiates a perilous ritual described in the book, designed to detect and expel demons. This ritual compels each family member to interact with the demon through their own distinct method: by seeing, hearing, or speaking to it.