A Dario Argento horror along the lines of 'Phantom of the Opera'. Betty (Christina Marsillach), a young understudy at the opera house, finds herself in demand when the female lead in Verdi's Macbeth falls ill. Whilst on stage, her fears about the curse of Macbeth begin to ring true as a stagehand is murdered and several ravens used in the production are killed. Betty is then taken captive by the murderer, tied up, forced to have her eyes pinned open and then witness the murder of two other people. The police inspector assigned to the job, Santini (Urbano Barberini) realises that ravens never forget and releases the remaining birds so that they can find the murderer. This leads to a chain of gory events, eventually revealing who the killer is and what his connection with Betty is.