While driving through the countryside late at night, Dr. Benson finds a crashed car with a woman hanging out of it. The doctor puts the girl in his car drives for help to the nearest house, which turns out to be a mysterious castle. When he knocks on the door he is greeted by a woman who looks exactly the same as the injured woman. This woman invites them both to stay for the night and the doctor soon discovers that his host is not the only one in the castle, and that this beautiful woman is concealing a terrible secret...

This is Italian gothic at its most demented, with lashings of 1970s-style sex, whippings, Satanism, lesbianism, nudity, dubious haircuts and a lust-crazed arachnid with a taste for sadomasochism and women in stockings. A truly extraordinary film!