Figaro and Susanna, servants of Count Almaviva, are preparing to celebrate their wedding which is to be held later that day. Susanna, however, is concerned that the Count has been making advances toward her. She believes their bedroom is too close to the Count’s, allowing the Count to visit Susanna easily when Figaro is attending to their master’s needs. This shakes Figaro’s confidence, but he leaves determined to confront the Count.
As Figaro leaves, Marcellina, a housekeeper, arrives with Dr. Bartolo, her legal counselor. Marcellina is furious with Figaro, as he had promised to marry her if he could not repay his loan. Bartolo, meanwhile, has his own score to settle, as Figaro thwarted his plan to marry the Countess. Susanna scolds Marcellina and she leaves shamed.
Cherubino, a young pageboy, enters and confesses that he is in love with the Countess. At that very moment Susanna hears the Count coming and hides Cherubino. The Count enters and confesses his love for Susanna, requesting they be alone. Before Susanna can answer, footsteps are heard outside the door, forcing the Count to hide. Don Basilio enters Susanna’s room to speak with her about Cherubino’s desire for both Susanna and the Countess. Hearing this, the Count becomes enraged and reveals himself and Cherubino in the process.
The Countess and Susanna are in the Countess’ chambers. The Countess is distraught over the Count’s suspected infidelity and prays for his affections to be restored. Susanna tells her of the scheme to catch the Count – Cherubino will dress as a girl and attempt to seduce him. As Susanna is dressing Cherubino, he tells the Countess he loves her, and eventually wears her down. Just as he is about to win her over, the Count knocks on the chamber door, claiming an anonymous letter informed him of his wife’s affair with Cherubino.
The Countess hastily shoves Cherubino into the closet to hide him from the Count. The Count begins questioning the Countess about who may be in her room. As he interrogates her, a voice calls out from the closet. The Countess tells him it is Susanna. Susanna, meanwhile, has secretly entered the room and is eavesdropping on the conversation. The Count leaves with the Countess to find tools to open the closet door. Susanna opens the door, removes Cherubino, sends him out the window and takes his place in the closet.
The Count and Countess return to the chamber. The Countess, sure she will be caught, confesses that it is actually Cherubino in the closet. The Count vows to kill Cherubino, but is shocked to discover that it is in fact Susanna in the closet. Thinking quickly, the Countess tells the Count it is a practical joke designed to test his trust in her. Feeling ashamed, he begs for forgiveness but wonders about the anonymous letter. Susanna and the Countess claim it was written by Figaro, who enters at that moment. The Count interrogates him about the letter, but Figaro satisfactorily answers all of his questions. Just as the Count’s suspicions begin to dissipate, the gardener, Antonio, enters. He is angry about his flower beds, which were destroyed by Cherubino when he climbed out the window. Figaro claims he jumped out the window, but Antonio shows a piece of paper that the man dropped. Figaro is unaware that the paper is actually the Count’s appointment of Cherubino to the army. The Count, suspicious, asks Figaro about the document. With help from Susanna and the Countess, he correctly answers the Count’s questions. At that moment Marcellina, Bartolo, and Basilio enter and accuse Figaro of not honoring the marriage contract. The Count, eager to dispatch Figaro, happily obliges their plea for a trial.
At his hearing, Figaro is ordered to honor the marriage contract. Figaro claims he needs his parent’s permission to marry, but he does not know who they are. They eventually determine that Figaro is the long-lost son of Marcellina and Bartolo. In celebration, Figaro embraces Marcellina. Susanna, seeing this embrace, believes that Figaro has chosen Marcellina over her and slaps him. Marcellina explains that she is Figaro’s mother. Susanna joins them in celebration before agreeing to a double wedding with Marcellina and Bartolo.
Before the wedding, Susanna tells the Countess of her plan to catch the Count. The Countess dictates a letter to Susanna to confirm their meeting. She tells her to seal it with a pin and take it to the Count, so that the Count will bring it with him to their meeting under the pines.
The Count gives Barbarina the pin to return to Susanna. Barbarina, however, loses the pin. Figaro finds Barbarina searching and asks what she is looking for. She tells him, and, feeling betrayed, Figaro vows revenge.
Figaro hides as Susanna and the Countess arrive, dressed as each other in order to deceive the Count. In the dark, Cherubino enters and flirts with the Countess, who is dressed as Susanna. The Count arrives and dispatches Cherubino. The darkness leads to confusion as the Count seduces the Countess, believing she is Susanna. The real Countess enters and reveals herself. The Count, realizing his error, begs for forgiveness. The Countess, being kinder and gentler than her husband, forgives him and all assembled celebrate.