Figaro and his soon-to-be wife, Susanna, are in their new bedroom where they are supposed to live after their marriage. Susanna does not like the new room because it is too close to the Count's room, who want to seduce her.
Meanwhile, Dr, Bartolo promises the housekeeper, Marcellina, that he would help her marry Figaro, who had once promised to marry her. Bartolo wanted to get revenge on Figaro for foiling his plan to marry the Countess.
Back in Figaro and Susanna's room, Cherubino enters and confesses that he is in love with the Countess, but the Count had caught him with Susanna's cousin and the daughter of the gardener, Barbina.
When the Count arrives to beg Susanna for a tryst, Cherubino hides under a chair.
Don Basilio arrives, and the Count seeks for a hiding place. He heads for the chair Cherubino is hiding under, so Cherubino jumps into the seat and Susanna covers him with a cloth.
When Don Basilio begins to gossip about Cherubino and the Countess, the Count jumps out. Don Basilio assumes that the Count and Susanna are in a relationship, causing Susanna to faint.