Camilla writes Anselmo that she is ill at ease. She will go to her parents house, even if it means deserting his household. The man he left to protect her cares more about his own pleasure than protecting his friend's wife.
Anselmo is pleased by her response. He orders her to remain at the house, saying he shall return. Camilla obeys, since she realizes her flight might give the servants reason to gossip. She fears Anselmo may accuse her of encouraging Lothario and causing a quarrel between them. She starts tryingto find a way to excuse Lothario.
Lothario continues to press his suit, and she begins to waver and finally falls. Camilla's maid knows this.
When Anselmo returns, Lothario tells him Camilla resisted him. He tells Anselmo he has a worthy wife and to stop testing her. Anselmo is satisfied, but he encourages Lothario to continue his courtship--for it amuses Anselmo.
Anselmo asks Camilla why she wrote the letter. She tells him she thought Lothario acted more freely with her, but he hasn't lately--and now she thinks it is him imagination. He tells her Lothario loves another. Camilla is already is aware of this other girl and doesn't react with jealousy.
Anselmo has Lothario recite sonnets he has supposedly written to this other girl. Camilla believes they are really for her.
Camilla relies on her maidservant Leonela to help her with her affair with Lothario, and she becomes more dependent on this servant--who could ruin her if she wished. She also helps Leonela see her lover.
One day, Lothario sees Leonela's lover leave the house and believes he was there to see Camilla. He goes to Anselmo and tells him that Camilla has yielded. He encourages Anselmo to react with revenge. However, he regrets his actions later, so he decides to reveal everything to Camilla.
Camilla tells him how she has been forced to allow Leonela's lover to enter the house and stay, at the risk of her own reputation, because Leonela can reveal her relationship with Lothario. Lothario believes her and tells her everything. She is angry, but she figures out a way to remedy the situaiton.
Lothario tells Anselmo to hide himself so he can catch Camilla. Anselmo does so. Camilla enters and tells Leonela she should kill her with Anselmo's dagger for the ruin Lothario has caused with his lies. Leonela suggests they kill Lothario, and Camilla agrees. She'll kill Lothario and then herself.
Lothario is in on the act, but then he begins to wonder if Camilla really is play acting. She injures herself and falls faint on the floor. He realizes she only gave herself a flesh wound, so he continues to cry over her as if she is dead. However, they reveal she isn't completely injured.
Anselmo is delighted at his wife's purity and goes to Lothario, who is relieved that he believes the act. The falsehood is maintained until the story comes out when it is printed abroad.