The balance of good and evil is an essential element of the world we live in. The struggle between God and Satan is central to this balance--for as much of an influence of beauty and good God has in our mortal realm, so it is the sworn duty of the Evil One to oppose him, to denigrate him, to tear down and degrade his finest creations.
In the 18th century, God brought into the world a perfect artistic mind--the musical genius Wolfgang Amadeus Mozart. His compositions would change the world, creating a direct conduit to the divine through human artistic creation. And so, it was entirely predictable that the forces of Hell would do everything in their power to destroy him...
The vessel chosen by Satan would be one Antonio Salieri, a mediocre court composer in Vienna who once adhered to the precepts of Christ and humbly did his best at creating music for the Emperor of Austria. But when the now-grown former child prodigy Mozart arrives in Vienna, something stirs in Salieri that provides just the opening the Devil requires. Consumed with unreasoning jealousy, and unable to comprehend how a God-fearing man like himself could be so utterly eclipsed by a childish and vulgar fop like Mozart, Salieri begins to be filled with unreasoning jealousy and contempt.
Plunged deeper into a pit of despair with every accolade heaped upon the young German composer, Salieri begins to know violent, bloody, homicidal thoughts. He rejects Christ utterly, casting the crucifix into the fire and accepting the forces of Darkness as his new guiding impetus. If he cannot be like Mozart, he reasons, then he must annihilate Mozart. If God would choose such a man to be his vessel, than Salieri would make it his life's work to spit in the face of God and ruin his perfect creation. Satan was bent on having the last laugh this time.
But in order to accomplish the murder of Mozart, more pieces of the puzzle are required. Ever the opportunist, vengeful Lucifer identifies Mozart's greatest weakess--namely, his need to please his overbearing, manipulative father, Leopold. Bringing about his sudden death, the Enemy of God returns his immortal spirit to the living world, to do his vile bidding in an alliance with Salieri.
Possessed by the ghost of Leopold Mozart, Salieri hatches a vicious plot to crush Mozart's sanity, and his life. Dressing in the same macabre costume once worn by Mozart's father at a masquerade ball, Salieri visits his archrival, demanding in anonymity that he write a mass for the dead. The room rank with the cruel presence of his father's unkind spirit, Mozart's realizes the true meaning of what's being asked of him.
His guilt at disappointing his dead father driving him relentlessly, Mozart hurls himself into the composition of the Requiem Mass. Haunted constantly by his father's disapproving ghost, the composer slips further and further into financial ruin, drug addiction, and woefully poor health. Slowly but surely, Salieri's Satanic scheme saps away the life force of God's brilliant and beautiful creation.
At long last, confined to his death bed, Mozart is visited by none other than Salieri, who sees to it that the final nails are driven into the coffin, pushing his rival into the grave, while also completing the dreaded mass of death. Satan's hateful plan completed, the fearsome music created on that night becomes Mozart's own death mass, played before his bloated corpse is dumped in an open, unmarked grave to decay and be eaten away with lime.
Reveling in his apparent triumph, Salieri believes he has won the day. However, doing the Devil's bidding always has its price. In the case of Salieri, that price is the loss of his mind as a result of the gnawing guilt of the evil he has committed. Driven to madness, the once humble, religious man is twisted into an aged mockery of his former self, living out the rest of his life caged up like an animal with the cast-off horrors of the so-called Enlightenment Era. God's vessel has been destroyed. And in the end, so has Satan's.