Description
In 1920s England, a group of upper-class people take part in an automobile race to Land's End. One couple, Daphne and Billy, get lost in heavy fog and run out of petrol. Billy goes to look for fuel, but takes so long that Daphne strikes out on her own. She locates a rural estate owned by Dr. Lawrence, a former priest. He receives her kindly and sends his disturbed gardener, Tom, to find Billy. Tom finds Billy asleep in the car and kills him by pushing the car with him inside over a ravine. It is implied he acted on his master's orders.
Meanwhile, Lawrence tells Daphne about a trip his family took to India; his experience with certain cults there horrified him so much that he renounced religion in general. This decision was heavily influenced by the fate of his wife and son, who were converted to a new faith by a local nobleman. The former was afterwards so horrified by the things she had done that she committed suicide.
Still waiting for Billy, Daphne falls asleep in a guest room. Seeing this, the doctor's Indian housekeeper, Ayah, goes to the attic and lets out a bloated, blood-stained man in a priest's mantle. He kills Daphne with a katar, and Ayah ritually cooks the girl's flesh for him to eat and burns the girl's clothes.
The first couple's friends, Geoffrey and Angela, learn of Billy's death from the local police and set out on a private mission to find Daphne. They too wreck their car and are separated in the search for help. The police refuse to search the marshlands as it is too dangerous. Angela locates the Lawrence estate and is abducted by Tom, who tries to rape her. When Lawrence discovers her presence, he reluctantly decides to use her as another sacrifice to the ghoul in his attic. Angela is saved from molestation when Tom is sent to get rid of Geoffrey, who found the estate first and was convinced by Lawrence that Angela and Daphne were both safely escorted back into town.
Tom botches his attempt to kill Geoffrey and is half-sucked into a bog in his attempt to flee. Before he is rescued, he is ordered to explain himself and admits that Daphne was fed to something living in Lawrence's house. Geoffrey returns to the estate and confronts Lawrence, who admits that the ghoul is his own son; the man has been a cannibal since his conversion, and Ayah is another cult member who came from India to prepare his food. Lawrence has tended to and taken care of his son because he promised his wife he would do so.
Geoffrey barges into the attic and confronts the ghoul, who kills him. Meanwhile, Tom sneaks into the room where Angela is imprisoned and tries again to rape her, but is interrupted and killed by the ghoul, who has gone out of control. The creature attacks Angela, but Lawrence enters with a pistol and fatally wounds it. Angela runs screaming from the house. Heartbroken by what has happened, Lawrence goes into his study and shoots himself through the head.
