Russia, 19th century. Antonina Miliukova, a wealthy and gifted young woman, falls in love with the composer Pyotr Ilyich Tchaikovsky and manages to become his wife. For him, the marriage is meant to silence rumours about his homosexuality; for her, it is a dream come true. Violently rejected, Antonina is willing to endure anything to stay by his side, and her love slowly turns into an obsession that drives her to madness.