Trying to regain Othello's favor, Cassio hires musicians to play beneath his window. But Othello sends down a clown, or servant, who mocks the musicians and sends them away.
The musicians serenading create another scene within a scene.
Cassio gives the clown a gold piece, and asks the clown to bring Emilia to him so that he may speak with her. The clown exits and Iago enters. Cassio explains that he sent the clown to get Emilia. Iago says that he will send Emila down himself, and will also make sure that Othello does not come near so that they will be free to talk. Cassio thanks him for his kindness and honesty. Iago exits.
Following Iago's final soliloquy in 2.3, the audience knows that no good can come of Cassio's seeking Desdemona as his advocate. The fact that even Emilia plays into Iago's manipulations draws attention to how limitless Iago's capacity for deception is: he will even use his own wife.
Emilia enters, and tells Cassio that Othello and Desdemona have been talking about his situation. Desdemona spoke strongly in his favor. Othello responded that because Montano is so powerful and well-liked in Cyprus he can't simply give Cassio his job back. However, Othello also told Desdemona that he loved Cassio and that he is looking for the earliest opportunity to reinstate him. Even so, Cassio begs Emilia to help him have a brief conversation with Desdemona. Emilia agrees to help him.
Emilia's report on Othello and Desdemona's conversation about Cassio's fate underlines the extreme differences between the Othello-Desdemona and Iago-Emilia couples. The first is based on mutual respect and love, in the second, Iago keeps Emilia completely in the dark and uses her for his own ends.