When Ludwig van Beethoven dies, his assistant and close friend Schindler deals with his last will and testament. It reads that his estate, music and affairs will be left to his "immortal beloved", but there remains a question as to who is Beethoven's "immortal beloved", an unnamed woman mentioned in one of his letters. Schindler embarks on a quest to find out. He meets the women who played a part in Ludwig's life; through their stories, retrospective footage of Beethoven from his younger years until his death is featured as the film progresses. The conclusion ultimately is that the individual is Johanna van Beethoven, the daughter of Anton Van Reiss, a prosperous Viennese upholsterer. In the film, she becomes pregnant by Beethoven; when by an accidental turn of events he does not marry her in time, she marries his brother, Kaspar Anton Karl van Beethoven. The love turns to hate, worsened by the long legal battle over custody over their son, Karl van Beethoven (whom everyone believes is Beethoven's nephew). Finally, Ludwig gets custody over his 'nephew', but the strict upbringing and promotion of the boy as another child prodigy—which Karl himself knows all too well he is not—leads to his attempting suicide. Beethoven is blamed and his reputation is ruined.