The polar-opposite worlds of opera and horror collide in this gory giallo film from director Dario Argento. Christina Marsillach (Tom Hanks' romantic interest in Every Time We Say Goodbye) stars as Betty, a beautiful understudy who gets an unlikely break to play the female lead in a contemporary opera of Verdi's Macbeth.
Her fear of Macbeth's notorious curse proves to have foundation when a psychopath with a strange connection to Betty murders a stage hand in the midst of her debut and later kills several ravens being used in the opera.
Characters introduced at this point who could be the killer include: the show's director, Marco (Ian Charleson); Betty's publicist, Mira (Daria Nicolodi); and the police inspector, Alan Santini (Urbano Barberini). The middle third of the film is devoted to the killer's bloody work which serves to torment Betty.
The madman binds her and tapes a row of tiny needles beneath her eyes so that she is forced to watch him butcher a young stage manager and a costume designer, among others.
With the police investigation going nowhere and the killer zeroing in on Betty's death, Marco decides to enact his own plan to stop the madman; he releases the ravens (apparently, they always remember their enemies) during a performance. The birds circle wildly before attacking the killer and plucking one of his eyeballs out.
He absconds with Betty, but dies in a fire after revealing his demented motivation and his connection to the young singer. A final scene set in the Swiss mountains provides a couple of final shocks.