Betty, a young up and coming opera singer opera singer, gets put in the lead role of Verdi's Macbeth after the leading lady storms out of rehearsal and gets hit by a car (breaking her leg). However, she believes that the opera is bad luck for all involved and is quickly proven right when people start dying, violently. The film is considered by many to be Argento's last true masterpiece. Fittingly for the film's play within a play, the film itself is largely known for it's behind the scenes ending troubles: