As a boy, Salieri desired to develop and display his musical talents. But his father had other plans. He was determined to make his son to become a successful businessman just like him. The young Salieri then prayed, "Lord, make me a great composer. Let me celebrate Your glory through music, and be celebrated myself. Make me famous throughout the world, dear God. Make me immortal. After I die, let people speak my name forever with love for what I wrote. In return I will give You my chastity, my industry, my deepest humility, every hour of my life."

Shortly afterwards, his dad choked on something he ate and died. Having no doubt that God had answered his prayer, Salieri went on to pursue his dream. He eventually became the court composer for Emperor Joseph, the musical king. Salieri was a hot palace favorite till Mozart’s arrival.

Mozart was initially employed by the Archbishop of Salzburg. Salieri came to know about Mozart’s music, and traveled to the Archbishop’s palace to hear him. He had never met the young man before. Before the performance of the symphony, all the guests were served food at the banquet hall.

Salieri wondered as he looked out for Mozart, "Is talent like that written on the face? Which one could he be?" While he was alone in a room, a young woman ran in and hid underneath one of the tables. Seconds later, a man, who was chasing her, rushed in and found her under the table. Both of them began to embrace and kiss on the floor. This young man was in his twenties. His appearance was vulgar, obscene and repulsive to Salieri.

Salieri later got the shock of his life. The giggling and indecent creature rolling on the floor was the same one conducting the orchestra. Mozart! His music was heavenly! Salieri described these thoughts to the priest, "This was the music like I had never heard, filled with such longing. It seemed to be the music of God. Yet why would God choose such an obscene child to be His instrument?"

Mozart’s fame reached the Emperor’s courts. He was invited to the palace. The king commissioned him to write an opera. Salieri tried to compose a little march of welcome for the occasion. But when Mozart heard it, he scoffed. In the presence of the Emperor and other court musicians, Mozart sat down to rework on it. Salieri was utterly humiliated in disgrace!

Salieri related this to the priest, "All I ever wanted was to sing to God. He gave me that longing, and then made me mute! If He didn’t want me to praise Him with music, why implant the desire like lust in my body, and then deny me the talent?"

Mozart further outraged Salieri by stealing his beautiful pupil, Katherina. He even slept with her. In his confession, Salieri said, " I was in love with the girl – at least in lust. But I never touch her! … It was incomprehensible. What was God up to? My heart was filling up with such hatred for that young man. For the first time in my life, I began to have violent thoughts."

Mozart soon married his girlfriend, Constanze. They put up their home in Vienna. One day, Constanze came to seek help from Salieri. Her husband was spending more than he earned. They were in great debts. She had brought the scores of some of Mozart’s compositions for Salieri to examine whether they could be sold. She said, "They’re all originals. He doesn’t make copies."

When Salieri saw the music scores, he was overwhelmed. He told the priest, "It was beyond belief. These were first and only drafts of music, but they showed no corrections of any kind – not one. He had simply written down music he had already in his head – page after page of it, as if he was just taking dictation. And music finished as no music is ever finished. It was clear to me – that sound I had heard in the Archbishop’s palace had been no accident. Here again was the very voice of God."

Salieri could not contain his fury anymore. Those scores of Mozart were far more superior than his! When Constanze left, Salieri removed the crucifix hanging on the wall and threw it into the fire. He began to hate God, "From now on we are enemies, You and I. Because You choose for Your instrument a boastful, lustful, infantile boy and give me for reward only the ability to recognize the incarnation. Because You are unjust, unfair, unkind, I will block You. I swear it. I will hinder and harm Your creature on earth. As far as I am able, I will ruin Your incarnation."

From that time onwards, Salieri pretended to be friendly to Mozart while he secretly plotted and schemed to destroy him. By compelling Mozart to work when he was already exhausted, Salieri brought about his untimely death.

Thirty-two years later, Salieri was still tormented by what he did. He was still angry with God. Venting his anger upon the priest, he howled, "Your merciful God…. He destroyed His own beloved. He killed Mozart and kept me alive to torture – thirty-two years of torture, slowly watching myself become extinct. My music grew fainter, all the time fainter, while his grew louder and louder."

At the film’s final scene, Salieri had to face himself, and he declared, "I will speak for you, Father. I speak for all the mediocrities in the world. I am their champion. I am their patron saint. Mediocrities, I absolve you."