In a very cunning manner, Iago plants the notion of infidelity in Othello’s mind. While reminding him of that handkerchief, he says that Cassio has seduced Desdemona. Othello falls in a trance. Cassio enters and notices Othello’s state of unconsciousness.
Iago turns him away and Othello gains consciousness and Iago further makes him suffer from his treacherous words about Desdemona’s betrayal and further plans about talking to Cassio about Bianca and her love for him which will but make him laugh and Othello in his jealousy will misinterpret it for sure.
Bianca enters at the same time and from distance, Othello notices the handkerchief in her hand. When they leave, Iago tells Othello what he was already thinking. Othello in complete fury decides to kill both of them. Iago suggests Othello kill her on the very bed where she has deceived him.
Desdemona enters with Lord Lodovico who brings a letter from the Duke and on her demand for reconciliation with Cassio, Othello reacts violently and when she starts weeping, he shouts at her tears as false ones. Lodovico leaves and on his way, Iago suggests him of Othello’s nature which he noticed inside.
Othello meets Emilia and asks her regarding Cassio and Desdemona to which Emilia reacts with the truth that she has never noticed any such activities between them. Othello doubts her truthfulness.
Desdemona enters and he presses upon her further the accusations which are there in his mind. He calls her whore and a faithless wench. Emilia and Iago meet her too and Emilia discusses the ways which could have poisoned Othello’s mind.
Desdemona asks Iago to convince him into the right path of thinking. Roderigo impatiently meets Iago and threatens him of asking Desdemona directly of all those presents and money he kept sending for her through Iago. Iago convinces him otherwise and asks him to dash his brain out in a coming situation.
Othello asks Desdemona to stay on the bed and he walks out with Lodovico. Desdemona and Emilia talk about her love and how she loves him nevertheless. They talk about the nature of faith and fidelity.
Emilia says that it is men from whom women learn how to sin. Desdemona bids goodnight to Emilia and confesses her inability to harm in return to the harm done to her.