The conveniently-timed deaths of a number of rich businessmen appear to have taken place shortly before they were due to receive large tax demands, arousing the suspicions of the Inland Revenue. The only common factor seems to have been their psychiatrist; Adam Adamant, posing as a harassed financier, makes an appointment with the man, who concludes from his patient's unusual mental history that he is suffering severe delusions and takes the opportunity to prescribe a stay at a sinister health resort.

A pleasant weekend party becomes a nightmare for one man when he finds himself involved in a black magic ritual and a human sacrifice.