Cassio wants to meet Desdemona. Iago, acting on his own plan, pretends that he will take Othello away so that he can talk to Desdemona more freely. Emilia, the wife of Iago, consoles Cassio of his misfortune.
Othello asks Iago to deliver some letters to the senate and meet him later where the fortification is going on.
Desdemona, Cassio and Emilia are talking in the garden of the castle. Desdemona believing in her husband’s goodness assures Cassio regarding his problem.
Iago enters with Othello and tries to make him notice Cassio going away after meeting Desdemona. Desdemona tries convincing Othello on accepting Cassio back into his official role. Othello agrees to her but he has started doubting her.
Using his brilliant rhetoric, Iago plants solid suspicion in Othello’s mind regarding the character of Desdemona who according to him is from a different lineage than that of Othello so she might’ve started repenting her marriage to him after coming closer to her own type i.e. Cassio.
Othello starts perceiving Iago as someone who is too honest and really cares about his wellbeing. Desdemona forgets to take the handkerchief which was Othello’s first token of love for her and it is found by Emilia who remembers Iago asking her to get it.
She gives it to Iago. Othello progresses further from jealousy into extreme agony of the false assumption of betrayal. Iago shows him the handkerchief and it completely infuriates him to settle for blood revenge. He decides to kill Cassio and Iago is promoted to be the lieutenant.
Desdemona is asking the clown regarding Cassio and Othello enters and his words are marked by his secret conviction regarding Desdemona’s infidelity. He asks her of the handkerchief which he gifted her and tells her how important it was to him as an inheritance.
Iago comes with Cassio and Desdemona talks to him about the current temper of Othello. Emilia notices Othello’s jealousy and both of them think of men’s attributes. Bianca comes and hears from Cassio who must wait for Othello.