The action, which takes place in Naples, tells the story of Diana, Countess of Belflor. Diana is a beautiful and stubborn young woman who is harassed by several aristocratic suitors who wish to marry her. However, Diana constantly rejects all his attempts. One night, after seeing her secretary make love to her favourite lady-in-waiting, she falls madly in love with him and becomes ill with jealousy. This is the story of a love triangle, of forbidden loves and betrayals, which happens when Naples was a Spanish city. Thus, the house of the Countess manipulated by the nobles represents that part of Spanish society that lived outside the country. The fact of placing the action in this European city also allows the work to be full of Italian influences and plots to which Lope de Vega was so fond.