Architect Maggie Walsh (Ross) is invited for a job in England, and goes there with her boyfriend Pete (Elliott). Their motorcycle crashes in the countryside when they almost hit the car of one Jason Mountolive (John Standing). He invites the two to his mansion for the duration of their ride's repairs. Staying there, it soon dawns on them that their arrival was no coincidence as odd, deadly accidents fall upon the other arriving guests.
Roger Daltrey, lead singer for The Who, appears in the cast.
This film has the examples of:
- Disturbed Doves: Doves scared by Jacques almost give away his position on the roof to Pete before he starts shooting.
- Failure Is the Only Option: When Maggie and Pete try to leave the mansion forcibly in a stolen car, they find themselves Going in Circles, no matter what road they take.
- Fainting: When Maggie sees Mountolive's true old and withered form, she faints on the spot.
- Hollywood Satanism: Of "rich people who gain power and wealth from forces of darkness" variety.
- Instant Drama, Just Add Tracheotomy: When Clive starts choking in the middle of a dinner, Nurse Adams tries to save his live with a tracheotomy. She was was very unlikely to succeed, since the bone Clive's throat didn't get there by normal means.
- Ironic Death: Most of the deaths of the supposed inheritors are related to the scandals they have been involved in.
- Man on Fire: A sudden burst of flames from a fireplace engulf Karl, and he is burnt to the bone after flailing around in agony.
- Mark of the Supernatural: The strange white cat in the mansion has differently colored eyes, which is a first hint that it is actually a shapeshifter.
- Really 700 Years Old: Jason Mountolive is actually about 300 years old, and uses his powers to make himself appear younger when needed to.
- Reincarnation: Maggie is a reincarnation of Margaret Walshingham, a powerful witch from the 16th century (who was burned as such), who is the mother of Jason Mountolive.
- The Reveal: Jason Mountolive himself has been killing his inheritors as a form of sacrifice so that all of his powers will be transferred to Maggie.
- Vanity License Plate: Downplayed with Jason Mountolive's car, which has the license plate that reads "JM 1".
- Voluntary Shapeshifting: The white cat that moves about in the mansion is actually Nurse Adams in animal form.