After Amadeus is dismissed from the Salzburg court for his wild and disrespectful behavior, his sister Maria Anna faces an even worse fate: an arranged marriage by their father, Leopold. To avert their mutual ruin, the siblings secretly flee to Vienna, hoping to secure Amadeus a new position at the court of Emperor Joseph II. What Maria Anna doesn't know is that her brother is suffering from a wrist injury, which he is treating with a mixture of laudanum and alcohol.

Constanze was accidentally shot during the duel. After tending to her, Amadeus is arrested. When the Emperor learns the reason for the duel, he announces a public aria competition to decide who will compose the national opera. At court, Marie Antoinette tries to seduce Amadeus, who flees at the last moment. The pressure becomes too much for him, and he sinks deeper and deeper into his addiction.