Gifted composer Wolfgang Amadeus Mozart moves to Vienna, destined for success and falling in love with soprano Constanze Weber. He soon meets esteemed court composer Antonio Salieri and secures his first opera commission from Emperor Joseph II. But when Salieri hears his music, he publicly dismisses Amadeus' talent, who in turn mocks Salieri's sexual stiffness. Maddened, Salieri then vows to kill Mozart.

The grief-stricken Mozarts are barely communicating with each other, while Salieri is promoted and assumes more power to pull the strings against Amadeus's success. Receiving another commission, Amadeus is inspired by a contentious banned book, leaving Vienna and Constanze to compose in secret. As war brews, Salieri plants a spy on the Mozarts and then organises a riot at Amadeus's opening night.