Oliviero Rouvigny, a failed writer and an alcoholic, lives in a crumbling mansion with his wife Irina, who is scared of Oliviero's cat, Satan, that used to belong to his late mother. To fight boredom, Oliviero organizes decadent parties for local hippies and humiliates and abuses Irina in front of the guests. After his mistress, a young student, is found murdered, Oliviero becomes the primary suspect.
The film uses many elements from Edgar Allan Poe's short story "The Black Cat", and acknowledges this influence in the film's opening credits.