After witnessing a man's death in a bizarre accident, Father Pergado goes on a spiritual retreat, where he encounters his alien double bent on world conquest.
19th-century London psychologist Charles Marlowe experiments with a mind-altering drug. He develops a malevolent alter ego, Edward Blake, whom his friend Utterson suspects of blackmailing Marlowe.
The Theatre of Death in Paris specializes in horror presentations. A police surgeon finds himself becoming involved in the place through his attraction to one of the performers. When bloodless bodies start showing up all over town, he realizes there could be links with the theatre.
After the original owner dies in a mental asylum, a man moves into an abandoned mansion with a sordid history. Meanwhile, a few locals conspire to steal a large amount of money, said to be hidden somewhere on the premises.