After Pedrillo exits, the Count calls him back.

The Count tells Pedrillo to make haste and clarifies his order to visit his regiment, whereupon he should learn whether Cherubin reported for duty and, if so, at what time.

As Pedrillo exits, the Count shares his concerns that he has been tricked. He is concerned that “some determined swine” will try to seduce his wife (145), even as he tries to seduce Suzanne. He resolves to question Figaro thoroughly as Figaro appears in the room.

Figaro arrives at the moment when the Count is beginning to wonder whether Figaro and the Countess are plotting against him. He is determined to “force [Figaro] to marry the old woman” (146). 

The Count notes that Figaro is late. He makes a joke that the servants now take longer to prepare themselves than the masters, to which Figaro responds that only the servants “haven’t got servants to help them” (146). The Count privately wonders what might happen if Figaro refuses the order to accompany him to London. He floats the idea, to which Figaro pretends that he is very interested in the role. This convinces the Count that Suzanne has not told Figaro about what he said to her. Figaro compliments the Count’s generosity, claiming that he and his wife are looking forward to their life “in deepest Andalusia” (149).

The Count and Figaro test one another, each keen to know whether the other is engaged in a plot. The Count asks just how much Figaro was paid by the Countess to take part in the farce in her bedroom. Figaro responds that he received just as much from her as he received from the Count himself in exchange for orchestrating the marriage between the Count and the Countess—that is to say, nothing. They swap barbed comments, with Figaro showing off his wit.

Figaro and the Count talk about politics, though Figaro shares his distaste for the political world as he believes it to be populated only by self-interested people who say nothing of substance. Politicians pretend to be busy and concerned for the good of the people, he says, while actually engaging in corruption or duplicity. 

Figaro promises that he will stay behind rather than accompany the Count to London. He offers to watch over the Countess while the Count is away. The Count becomes sure that Figaro is conspiring against him and that he has “been told everything” (150). He is more determined than ever to marry Figaro to Marceline.

The conversation is interrupted by a footman announcing the arrival of Don Gusman Brid’oison, the Count’s legal officer. The Count sends a message that Don Gusman is to wait.

Alone again with the Count, Figaro asks whether the room is ready for the trial. Figaro believes that everything is ready, and he is eager to begin.

Alone, the Count notes the way in which Figaro can “run rings” around unsuspecting people. He believes that Figaro and Suzanne have joined forces again.

Suzanne arrives, out of breath. She is shocked by the Count’s angry reaction to her arrival. Suzanne asks the Count for his “smelling bottle”: The Countess is feeling faint, and she needs to be revived. 

The Count tells her that he plans to marry Figaro to Marceline, at which point Suzanne agrees to meet him in the garden in exchange for the dowry money that he promised her, which she can then use to pay off Figaro’s debt to Marceline. The Countess has already told Suzanne to allow the Count to believe that she is ready to embark upon an affair. In exchange, however, Suzanne demands that the Count must allow her to marry Figaro. This plan pleases the Count. He looks forward to their affair as Suzanne confesses that the smelling bottle was “an excuse” to talk to the Count. He exits, convinced that he and Suzanne will have an affair.

Suzanne meets with Figaro. They believe that they have lured the Count into their plot, so Suzanne tells Figaro to go to court because the Count will allow him to win his case.

Unbeknownst to them, however, the Count is eavesdropping on them from a hiding place. He is enraged to overhear that they are actually plotting against him, taking him for a fool once again. He is determined more than ever that Figaro will marry Marceline. If, somehow, Figaro wins the case, then the Count believes that he can rely on Antonio. Suzanne is Antonio’s niece, and the Count does not believe that he will allow Suzanne to marry “a nobody.”

Marceline, Doctor Bartholo, and Don Gusman enter. Don Gusman has a stutter. He listens carefully as Marceline explains her version of events. Don Gusman insists that the case is “ker-crystal clear,” though he struggles to keep up with the details.

As the matter is being discussed, Figaro enters. Don Gusman recognizes him, so Figaro explains that he was once in the service of Don Gusman’s wife. He flatters Don Gusman, who agrees to take a “special interest” in the case.

As the trial begins, the Count sits alongside Don Gusman. He is surprised that Don Gusman is in full legal regalia, but Don Gusman states that people laugh at judges in less formal dress while they quake “at the mere sight of a prosecuting counsel in full dress” (156). The usher announces that the court is now in session.

A series of cases is brought before the court. The Count dismisses each of them in turn. Then, Figaro’s case is announced. 

A major issue involves Figaro’s apparent lack of a surname. He typically goes by Figaro “Anonymous.” The Count questions Figaro, introducing himself as a gentleman, then Figaro defends his decision to act as his own attorney. Don Gusman presides. 

He calls on Bartholo to read the document in which Figaro supposedly promises to marry Marceline. Figaro disputes the details of the letter, insisting that he promised to pay the debt to Marceline or to marry her. In Bartholo’s reading, however, the author of the letter seems to promise to settle the debt and then marry her. The exact wording of the letter becomes a point of contention that the court must consider, since there is a “blot” on the original letter. Bartholo and Figaro argue back and forth about grammar and construction,

Eventually, the court issues a judgment: Figaro will either pay the debt or marry Marceline. Figaro, from thinking that he has won, immediately realizes that he does not have the money, so he will have to marry Marceline. Antonio, watching, is pleased that Figaro will not marry his niece.

The Count is delighted to have his “revenge” against Figaro. The court disperses, with Figaro insisting that he will not marry Marceline. He insists that he cannot do so, since he has not received permission from his “noble parents.” In response, the count inquires as to the identity of Figaro’s own parents. Figaro is dismissive; he insists that the Count would not know them. He himself has spent five years trying to find them. Figaro tells the Count that he believes that he was lost as a child and that all he has to identify himself to his parents is a birthmark in the shape of a spatula on his left arm.

As Figaro is about to reveal the mark, Marceline stands up. As Bartholo suggests that Figaro may have been “stolen” by Roma people, Marceline recognizes the sight of the birthmark. She refers to Figaro as “Fernando,” and Bartholo reveals that Figaro is actually her son. Marceline criticizes the powerful “unfeeling men” of the world who take advantage of women. Figaro embraces his mother as Suzanne and Antonio return.

Suzanne has with her the money that is supposedly owed to Marceline by Figaro. It was given to her by the Countess. The Count feels as though everyone is “conspiring” against him.

The sight of Figaro embracing Marceline concerns Suzanne, but Figaro explains the recent revelations to her. Marceline hugs Suzanne and offers her blessing to the marriage. Marceline believes this turn of events makes sense, claiming that this explains why she is so fond of Figaro. He responds that this must also explain his aversion to her, since instinct is very powerful. 

Suzanne gives the money to Figaro, and everyone weeps together. As Suzanne’s uncle, Antonio speaks out against the marriage. He does not consent to his niece marrying the illegitimate Figaro.

Marceline and Bartholo are persuaded to marry, thus legitimizing Figaro and enabling him to marry Suzanne. Figaro announces that they must find the Count before the Count comes up with “some new plot” to prevent the marriage (170).

Don Gusman is left alone, thinking how the people he has just met are not “very per-polite.”