At home, after Octavio speaks of his love for Isabela, Don Pedro comes to arrest him, claiming that Octavio had violated Isabela the previous night. Octavio, of course, had done no such thing, and starts to believe that Isabela has been unfaithful to him. He flees from Don Pedro, planning to leave the country.
By the seashore of Tarragona, a peasant girl named Tisbea happens to find Don Juan and his servant, Catalinón, apparently washed up from a shipwreck. She tries to revive Don Juan, who wakes and immediately declares his love for her. Tisbea takes Juan back to her house, intending to nurse him back to health and mend his clothes.
Back in Seville, the King speaks to Don Gonzalo, a nobleman and military commander, about arranging a marriage between Don Juan and Gonzalo's daughter, Doña Ana. Gonzalo likes the idea and goes to discuss it with his daughter.
Back at the seashore, Don Juan and Catalinón flee, apparently after Don Juan has already seduced Tisbea. Catalinón scolds him, but Don Juan reminds him that this is not his first seduction, and jokes that he has a medical condition in which he must seduce. Catalinón says that he is a plague for women. Tisbea catches up with the two men, and Don Juan assures her that he intends to marry her, but he takes it back just before he rides off. Tisbea is then immediately overcome with shame at the undoing of her honor and flings herself into the ocean, meaning to drown herself, but she is not successful.
That night at Don Gonzalo's home, Ana is heard screaming that someone has dishonored her, and her father, Don Gonzalo, rushes to her aid with his sword drawn. Don Juan draws his own sword and kills Don Gonzalo. With his final breath, Don Gonzalo swears to haunt Don Juan. Don Juan leaves the house just in time to find Mota and give him his cape back and flees. Mota is immediately seen wearing the same cloak as the man who murdered Don Gonzalo and is arrested.
Elsewhere Isabela and her servant, Fabio, are travelling, looking for Don Juan, whom she has now been instructed to marry. She complains of this arrangement and declares that she still loves Octavio. While travelling, they happen upon Tisbea, whose suicide attempt was unsuccessful. When Isabela asks Tisbea why she is so sad, Tisbea tells the story of how Don Juan seduced her. Isabela then asks Tisbea to accompany her.
Don Juan and Catalinón are back in Seville, passing by a churchyard. They see the tomb of Don Gonzalo, and Don Juan jokingly invites the statue on the tomb to have dinner with him and laughs about how the hauntings and promised vengeance have not yet come.
That same night, as Don Juan sits down for dinner at his home, his servants become frightened and run away. Don Juan sends Catalinón to investigate, and he returns, horrified, followed by the ghost of Gonzalo in the form of the statue on his tomb. Don Juan is initially frightened but quickly regains control of himself and calmly sits to dine while his servants cower around him. Gonzalo invites Juan to dine again in the churchyard with him, and he promises to come.
At the Alcazar, the King and Don Diego, Don Juan's father, discuss the impending marriage to Isabela, as well as the newly arranged marriage between Duke Octavio and Doña Ana. Octavio then arrives and asks the King for permission to duel with Don Juan, and tells the truth of what has happened to Isabela to Diego, who was until now unaware of this particular misdeed of his son. The King and Diego leave, and Aminta appears, looking for Don Juan since she thinks he is now her husband. Octavio takes her to the king so that she can tell him her story.
In the churchyard, Don Juan tells Catalinón about how lovely Isabela looks and how they are to be married in a few hours. The ghost of Gonzalo appears again, and he sets out a table on the cover of a tomb. He serves a meal of snakes, fingernails, and tarantulas, which Juan bravely eats. At the end of the meal, Gonzalo grabs Don Juan by the wrist, striking him dead. In a clap of thunder, the ghost, the tomb, and Don Juan disappear, leaving only Catalinón, who runs away in terror.
At the Alcazar, every single character who has been wronged by Don Juan is complaining to the King, when Catalinón enters and announces the strange story of Don Juan's death. All the women who have claim to Don Juan as their husband are declared widows, and Catalinón admits that Ana escaped from Juan before he could dishonor her. Mota plans to marry Ana, Octavio to marry Isabela, Tisbea is free to marry again if she chooses, and Batricio and Aminta go back home.
As a priest, Tirso creates this sinister tempter for didactical reasons. Don Juan is not solely representative of a youthful indifference; rather he is the personification of all that is sin and evil. Lucifer, across Christianity, is known as the Prince of Darkness; likewise, Tirso’s Don Juan carries out all his seductions at night. According to biblical passages, Satan does not live in Hell but rather roams Heaven and Earth in search of victims. Don Juan, like the devil, constantly prowls the Earth for his next prey.
Christian theology also dictates that the devil cannot deceive anyone without the person’s consent. In this case, Tirso’s Trickster cannot trick any of the women without their approval. Thus, although Tirso uses Don Juan to represent the devil, he is also used in order to critique Spanish conceptualization of honor. Rather than a reflection of human interiors, honor acts as a mask of sin.