In the historical context of the Austro-Hungarian Empire and the height of the Romantic era, the 19th century, Anton Bruckner, the famous Austrian composer and organist, falls in love with the imposing Countess Henriette. She had been appointed lady-in-waiting to Princess Charlotte of Belgium, the wife of Prince Maximilian of Habsburg, to attend to her during the couple's Mexican endeavor. They had been named Emperor and Empress of Mexico and would embark on a journey to America for this mission. Bruckner meets the countess by chance at the funeral of Maximilian, who had been assassinated in Querétaro in 1867, during the so-called Second Mexican Empire.

On the recommendation of a musician friend of Henriette's, who sees him at the funeral, she takes piano lessons with Bruckner. When she tells him that she had accompanied the empress to Mexico, the composer becomes enchanted. He admired Maximilian and was passionate about Mexico; he had even wanted to accompany the emperor. Ultimately, the only trips he made were to give organ concerts in London and another at Notre Dame in Paris. Between classes, the countess tells him of the Atlantic crossing, the arrival in Veracruz, and the entrance to Mexico City. Gradually, they grow closer. In one of his concerts, Bruckner meets Franz Liszt, who was a patron of Maximilian's empire in Mexico. Meanwhile, the countess and the organist plan a Requiem, which will be the turning point between them.