Musical comedy. Naples in the 17th century. Countess Diana de Belflor is in love with her secretary Téodoro but her social position does not allow her to bring her passion to fruition. However, she absolutely does not want Téodoro to marry Marcela, his lady-in-waiting. For his part, Téodoro is undecided, torn between his passion for Marcela and his wish to keep his place. It will be Tristan, Teodoro's servant, who will resolve the situation for his own benefit.