After Salieri fails to coerce Constanze into bed in exchange for the pupillage of Princess Elizabeth, he tells her of her husband's adultery. While trying to make peace with his father in Salzburg, Amadeus hears of his infant son's death.

The composer debuts Don Giovanni, inspired by his father's death, while Constanze leaves him for her lover. Deciding to finally seal Amadeus's fate, Salieri shuts down Mozart's opera and pursues him to the cheap vaudeville playhouse he has been forced to work in, setting him up for yet another failure.