Equipped with their costumes, the priest and the barber set out with Sancho to find Don Quixote and lure him home again. Sancho relates to them the saga of his adventures as they journey. When they arrive, Sancho goes on ahead, planning to tell Don Quixote that he has seen Dulcinea, that he has given her his letter, and that she begs for Don Quixote to come home to her. If Don Quixote still refuses to come home, the priest and the barber will go ahead with their plan to pretend to be a damsel in distress who seeks his assistance.
While waiting for Sancho to return, the priest and the barber encounter Cardenio, who tells them his story, this time including the conclusion that he failed to recount to Don Quixote. Cardenio explains that Ferdinand, while visiting Cardenio’s house, found a letter from Lucinda and was so taken with her that he devised a plan to win her for himself. Ferdinand sent Cardenio back to the Duke’s house and proposed to Lucinda. While at the Duke’s house, Cardenio received a letter from Lucinda begging him to come home because Ferdinand had proposed, her greedy parents had accepted, and she felt that she would soon kill herself. Cardenio rushed home just in time to see the wedding take place. Despite her words, Lucinda did not kill herself but instead accepted Ferdinand as her husband. Cardenio rushed away from the wedding and went out into the wilderness, driven mad with grief and hatred. Cervantes interrupts to say that the end of Cardenio’s story marks the end of the third part of the history by Cide Hamete Benengeli.
Before returning to the narration, Cervantes says that Don Quixote’s era is lucky that Don Quixote has brought back knight-errantry. Back in the story, the priest, the barber, and Cardenio meet a young woman named Dorothea, whom they initially take for a man because she is wearing a man’s clothes. Dorothea tells her tragic story. The incredibly beautiful daughter of a wealthy farmer, she happened to attract the attention of the son of her father’s master. The son wooed her persistently, but she resisted until one day when he appeared in her bedroom by trickery and swore to marry her. She succumbed to him because she was afraid he would rape her if she did not. He left town and abandoned her. Dorothea chased him in hopes of enforcing his pledge to marry her but discovered that he had already married someone else in a nearby town. She then relates the circumstances of that marriage, revealing that the son who falsely proposed to her was Ferdinand, the Duke’s son, and that his new bride in the nearby town was Lucinda. Dorothea tells them she then ran off into the wilderness out of shame.
Cardenio is thrilled to learn from Dorothea that when Lucinda fainted, Ferdinand found a letter on her that revealed her love for Cardenio. Cardenio vows to help Dorothea avenge the wrong Ferdinand has done to her. Dorothea offers to play the distressed damsel in the plot to lure Don Quixote home. Sancho returns with news that Don Quixote refuses to return to Dulcinea until he has won honor through penance.
The priest tells Sancho that Dorothea is Princess Micomicona, who is seeking Don Quixote’s help to redress a wrong a giant has done her. Sancho, the costumed Dorothea, and the barber, wearing a fake beard, find Don Quixote. In high poetic style, Dorothea beseeches Don Quixote to slay a giant who has taken over her kingdom. Don Quixote promises to follow her and not engage in any other adventures along the way. Sancho is pleased, believing he will now get his governorship. The priest and Cardenio overtake the party on the road. The priest greets Don Quixote, who recognizes neither the priest nor Cardenio. The priest tells Don Quixote that freed galley slaves have mugged him and the barber.
Dorothea weaves a story about the giant who has attacked her kingdom. She slips up several times during the story, even forgetting the name the priest has given her, and the priest has to interject to prevent her from revealing their ploy. Dorothea says she will marry Don Quixote after he vanquishes the giant, but Don Quixote refuses because he loves Dulcinea. His refusal upsets Sancho, who insults Dulcinea. Don Quixote beats Sancho. Just then, Gines de Pasamonte reappears with Sancho’s donkey and flees on foot. Cardenio and Dorothea discuss Don Quixote’s madness, and Cardenio remarks that Don Quixote is so crazy that he is sure no author could have invented him.