Task: Question Generation
Input (English): The film centers around young, insecure opera singer Betty (Cristina Marsillach). After the lead in Verdi's Macbeth is injured in a car accident, Betty is reluctantly thrust into the role in the opera. During her first performance, a murder takes place in one of the opera boxes. Mysterious murders continue throughout the film as Betty is stalked and those around her meet their unfortunate end. The killer binds and places tape under Betty's eyelids with needles attached so she is unable to blink, and therefore forced to watch as the murders take place. Meanwhile, Betty continues to have frightening dreams involving a masked person and her mother. During the final performance of the opera the killer is revealed, and Betty must confront her past in a terrifying climax.
Output (English): The killer is revealed in which performance?