At dawn, in the marble palace of a Prince, a nine-year-old sings for Wolfgang Amadeus Mozart, then at the peak of his career. Always delighted by musical children, he accepts Nanina as a pupil. Gifted, intense and imaginative, she sees the great "Kapellmeister Mozart” as an avatar of Orpheus and her own, personal divinity.
His lessons are irregular and playful, but the teacher/pupil bond grows strong. Mozart's The Marriage of Figaro premieres, and Nanina, now twelve, is given a solo part. For her, this is the beginning of a long stage career. For Mozart, it marks the start of his ruin. His greatest works will be composed in poverty and obscurity.
During the composer’s last summer, his wife has left him. Chronically in debt and suffering the emotional isolation of genius, he takes refuge with his disreputable Volksoper friends, who want him to write a “peasant opera” for their audience. Nanina, now grown, and still in love with Mozart, is among their number. As he seeks solace among the women of the Volksoper, the charms of his young fan become increasingly alluring. No one, least of all the composer, understands the depth of her obsession or how a brief affair will permanently alter her life.