Whilst on vacation in Greece, Richard Fountain (Patrick Mower), an Oxford don and the Foreign Secretary's son, falls into the evil clutches of Chriseis (Imogen Hassall), leader of a coven of perverted socialites who murder innocent victims in pursuit of their blood.

Richard's long absence from Oxford prompts his close friends Tony Seymour, fiancee Penelope and Bob Kirby to instigate a search for him.

The clues they find take them across the Aegan Sea to Hydra, a small island where two men find Richard drugged and unconscious in an old castle. A Pagan orgy is building to a climax as Chriseis is preparing herself for her next victim...

After a horrific struggle Chriseis flees, her mouth dripping with blood, and in a tussle with Kirby falls to her death. Richard is saved and returns to the sheltered life at Oxford, but the nightmare is just beginning...the spirit of Chriseis not yet dead!