Ever since her sister Nerina was seduced by Prince Alfonso and subsequently committed suicide, Violanta has fallen silent. All attempts by her husband Simone to coax her back to life have been in vain. Only the carnival in Venice brings her out of her self-chosen isolation.

Young Matteo is hopelessly in love with Violanta, the wife of his master, and is made fun of because of his infatuation. All others are swept up in the inebriating whirl of the carnival: “Even the dead from their graves / dance cheek to cheek today”.

Simone puts an end to the excess. He is concerned: Violanta has disappeared, and the painter Giovanni tells him that Alfonso is in town.

Violanta returns from a carnival party. She explains to her husband that she has set a trap for Alfonso: when the prince appears for their assignation, she wants Simone to murder him when a certain carnival song is sung. Violanta convinces her husband by piquing his jealousy while stoking her own hatred further and further.

Violanta prepares for her plan with the help of her maid Barbara. Night falls.

Alfonso’s seductive voice rings out in the night. Violanta believes she is dreaming. However, she is still unwilling to begin the song: she is increasingly mesmerized by this man, realizing that she is not driven so much by the urge to take revenge for her sister, but to stamp out her own desire. Violanta recognizes the bleakness of her life so far: “Sinful longing never shook me, / never did I – poor me! – live for myself.”

Violanta’s desire for fulfilment reaches the point of ecstasy. She sings the carnival song and is pierced by Simone’s dagger. She parts from him forever.