A baron fears his teenage children will go mad like their dead mother, so locks them in his castle and resorts to torture, drugs and cruel medical treatments to keep them under control. However, his son keeps escaping from the grounds to commit a series of murders. Hammer horror, starring Robert Hardy, Shane Briant and Gillian Hills.

A physician discovers that two children are being kept virtually imprisoned in their house by their father. He investigates, and discovers a web of sex, incest and satanic possession.