| Director | Dario Argento |
|---|---|
| Budget | $8 million |
Prima donna Mara Cecova storms out of a dress rehearsal for Verdi's Macbeth at the Parma Opera House, aggravated by the live ravens and by director Marco, known for his horror movies. Cecova is injured by a passing car, and the role of Lady Macbeth is given to her apprehensive understudy Betty, whose deceased mother was also an opera singer. After reassurances from her agent Mira, Marco, and her stage manager boyfriend Stefano, Betty's performance is successful. Meanwhile, a stagehand discovers an intruder watching the opera from a balcony box reserved for personnel and is murdered by being impaled on a coat hook.
Betty receives a poison pen letter from the resentful Cecova. That night, a masked figure breaks into the opera house and slashes Betty's costume to sew a gold bracelet into it. The figure is attacked by the ravens and kills three of them. Betty spends the night with Stefano at his wealthy uncle's unoccupied residence. Stefano is sympathetic about Betty's sexual dysfunction. When he goes to make tea, the masked figure suddenly gags Betty, binds her, tapes needles under her eyes, and forces her to watch as Stefano is stabbed to death. The killer gropes Betty, claiming that she is aroused, then loosens her bonds and flees. Betty reports the murder to the police from a nearby payphone. Marco drives her home, where she describes the ordeal and says that the masked killer resembled a figure in her childhood nightmares.
Inspector Alan Santini questions the opera staff about Stefano's murder and the raven attack. Betty later meets with seamstress Giulia to mend her costume. The killer reappears and constrains Betty in the same manner as before, then stabs Giulia, who swallows the bracelet. The killer cuts her throat open to retrieve it before loosening Betty's bonds and fleeing again.
Santini promises to send Betty his assistant Daniele Soave to her apartment building for her protection. Betty admits a man that she presumes is Soave, but Mira arrives and says she spoke to a different man claiming to be Soave in the lobby. Betty and Mira hide while the man takes a phone call and exits the apartment. Not long afterward, someone claiming to be Soave requests entry. Mira is fatally shot in the head while trying to verify the figure's identity through the peephole. Betty hides as the killer breaks into the apartment. She encounters the real, mortally wounded Soave, who reentered the apartment and was stabbed by the killer, and escapes through the ventilation system with the help of a neighbor girl.
Betty meets with Marco, who has a secret plan to identify the killer during a performance. Betty has a recurring nightmare in which she discovers her mother bound in a dilapidated room, with her face reflected in a mirror while a woman screams then falls silent, after which Betty glimpses the masked figure. During the following night's performance, Marco unleashes the ravens into the audience. Recognizing their attacker, Santini, the birds gouge out one of his eyes. Santini shoots at Betty and flees, then later abducts her from her dressing room.
Santini reveals that he was enamored of Betty's mother, who had him torture and murder young women for her gratification. Young Betty partially witnessed one such murder, which haunted her nightmares. Santini eventually killed Betty's mother due to her escalating demands and refusal to have sex with him. Betty's resemblance to her mother has now revived Santini's bloodlust. Santini blindfolds Betty, binds her to a chair, and stages his suicide by setting the room on fire. Betty breaks free and escapes.
Betty and Marco withdraw to Marco's house in the Swiss Alps to plan a staging of La Traviata. Marco sees a news broadcast indicating that a mannequin, not Santini, was burned in the fire, and that a manhunt is underway for Santini. He discovers that his housekeeper has been murdered and shouts for Betty to flee. Betty runs from the house, pursued by Santini. Marco tackles him, only to be stabbed to death. Betty bashes Santini on the head with a rock, and the police arrest him as Betty declares that she is nothing like her mother. Betty finds a lizard trapped in foliage and sets it free.