A busy summer's day in the spa town of Luhacovice. At the centre of attention is the beautiful Mila, who meets the composer Zivny, her former lover and father of her child. She explains that her mother forced her away from him in favour of a richer suitor. The couple are obviously still in love.
Four years later Mila and Zivny are living together with their four-year-old son, Doubek. Zivny is still wrestling with his opera in which Mila is jealously portrayed as unfaithful. Mila's insane mother is living with them and in a mad struggle falls down the stairs th her death, dragging Mila with her.
Eleven years later at the conservatoire where Zivny teaches. Students are preparing to perform his unfinished opera. He talks at length about his love for Mila and his music. A storm breaks out and as lightning strikes the room Zivny collapses and dies, saying that the last act of the opera is in the hands of God.