Iago tells Othello Desdemona went to bed with another man. Othello thinks Cassio is talking about Desdemona in a conversation he overhears. Bianca is angry because she thinks another woman gave Cassio the handkerchief he gave her. Othello slaps Desdemona because he thinks she is cheating. Lodovico watches the entire scene and is very unhappy. Othello smothers Desdemona. Emilia tells Othello that everything about the affair was untrue. Iago then tells Roderigo to kill Cassio to make all of his problems go away.