Looking from the balcony of her Madrid home, María watches Juan de Medrano ride by, courting her from a distance as he did for two years, and she is moved to confess to her servant Beatriz that she much prefers him to the more aggressive Don Diego. Juan is at last tired of seeing María only at a distance. That afternoon he comes to call, with the excuse that next day he is leaving for the wars in Flanders. María postpones their farewells until that night, when Beatriz will bring Juan to her.

Don Diego, too, decides on direct action. He arrives with a highly rhetorical demand for her affections. Claiming that she is unable to understand his proposal, María turns him down in the same kind of jargon. Angered, Don Diego directs his servant Morón to try to learn from Beatriz how María might be approached. Though the gift of a gold chain does not open her mouth, Morón knows that Beatriz will in time tell him everything.

Juan wants his friend Don Carlos to spread the story of his departure for the army, while actually he plans to stay in lodgings in Madrid. As a first step, he sends his farewells to Doña Violante, an errand that Don Carlos performs gladly because, with Juan away, he thinks he can win the lady for himself.

The next morning, as she sneaks Juan out of María’s house, materialistic Beatriz reflects on how silly aristocratic ladies are. They will not be seen talking to a man on the street for fear of gossip, but they are prepared to entertain him secretly in their rooms. This time, however, the assignation does not remain a secret. Morón worms out of Beatriz all the details of Juan’s visit and runs with them to his master. Don Diego elaborates on the event as he passes it on to his friend Antonio, and the story grows further as Antonio tries to elicit the true facts. Exasperated and resentful, Don Diego decides to confront María.

When Don Diego mentions Juan’s nocturnal visit, María is sure that her servant gossiped. To protect Beatriz, whom he loves, Morón explains that Don Diego is an astrologer who can summon up demons and who knows the past and the future. Don Diego does not deny this claim. In fact, when María’s father, Leonardo, comes up to them, he predicts an impoverished husband for her. The father, who had experiences with magicians, does not believe in them, and he would have unmasked Don Diego had Morón not cleverly saved his master from disclosure.

Don Diego’s friends, passing on the story, convince Doña Violante of Don Diego’s powers, and she begs him to materialize the absent Juan. To his protest that his power cannot cross water, she replies that, according to a letter just delivered by Don Carlos, he is in Zaragoza. At Don Diego’s prompting, Doña Violante writes Juan a letter inviting him to visit her. The note, mysteriously delivered by Don Carlos, brings Juan to her house. There he frightens her and he becomes thoroughly confused, since he knows nothing about the pretended astrologer.

Juan is more eager than ever to see María. Since Leonardo does not know him, he presents himself as a friend of Leonardo’s brother, just arrived from Zaragoza. María gives him a ribbon with a costly pin and tells him to sell it in order to provide himself with spending money. Then, scheming to bring him back to her, she tells her father that the pin was stolen. Leonardo hurries to consult Don Diego. Since Beatriz already babbled the new developments to Morón, Don Diego appears to have miraculous powers, and Leonardo goes in search of Juan. When he is discovered, Juan, fearing for María’s reputation, confesses to the theft. Angered, Leonardo refuses Juan’s request to marry María.

His supposed magic prowess brings Don Diego nothing but trouble. Even his servant claims a share in his strange powers and tries to send another servant on an aerial journey to his home town. Then Don Diego angers Doña Violante by refusing to give her a spell with which to kill Juan and María. He is, moreover, no further advanced in his own courtship. The conflicting prophecies he gives, hoping that some might come true, cause everyone to turn against him. Finally, when Beatriz explains how he secured his information, the mock astrologer renounces all claims to magic powers, but not before he accomplishes one good deed. When he reveals the whole truth about the jewel robbery, María and Juan are reunited.