Iago's disturbing suggestions about Desdemona aggravates Othello. Othello then falls into a trance. Cassio then comes in. Iago then offers Othello a chance to observe secretly as Cassio speaks of Desdemona. Iago then has a plan. He will make Cassio retell the story of where, when, how, and how often he has slept with Desdemona, and when he intends to do so again. When Othello withdraws, Iago informs the audience of his actual intention. Cassio makes light of Bianca, mocking her. Othello thinks he is speaking of Desdemona.
"I never knew that this woman loved you so much," stated Iago.
Cassio believes he is talking of Bianca. "Wha-What are you talking about?"
"She does tell everyone that she is going to marry you. Do you agree with this?"
"Ha. Never." Cassio starts laughing. "Marry me? Who does she thinks she is. This woman is out of her mind!"
"Well, faith says that you shall marry."
"You know what? Screw faith. I will never marry this woman. She is convinced I will marry her because I love her. But hell no, I do not love her!" yells Cassio, as his rage continues.
Othello then says to himself, 'now he begins to tell his story.'
"Thi-This woman is with me all the time. She stalks me everywhere I go. For example, the other day I was speaking to some Venetians, she comes up to me and puts a hand on my neck!"
Othello again is thinking to himself. ' She cries ''O Cassio,'' he just loves how she says that.'
"She is around me all the time. She is all over me and cries to me all the time. She NEVER LEAVES ME ALONE! Shouted Cassio.
"What ever you say Cassio."
"I never want to see her AGAIN!"
Bianca then enters with the handkerchief. She then again accuses Cassio of giving her a love token given to him by another woman. Bianca tells Cassio that if he doesn't show up for supper with her that evening, he will never be welcome to come back again. Othello then recognizes his handkerchief and, comes out of hiding when Cassio and Bianca are gone. He wonders how he should murder his former lieutenant. Othello goes on to grieve for his hard-heartedness and love for Desdemona, but Iago then reminds him of his purpose. Othello has trouble reconciling his wife's delicacy, class, beauty, and allure with her adulterous actions. Iago then suggests something to Othello.
"Iago, I believe I shall poison my wife. Her actions have caused me deep sadness."
"No, No, Othello. You shall strangle her in her bed. The bed that she contaminated through her infidelity."
"Aye, that is a most perfect idea Iago!"
"I shall also arrange for Cassio's murder as well."
"Thank you, Iago."
Desdemona comes in with Lodovico, who has come from Venice with a message from the duke. Lodovico irritates Othello by inquiring about Cassio, and Desdemona irritates Othello by answering Lodovico's inquiries. The contents of the letter also upset Othello—he has been called back to Venice, with orders to leave Cassio as his replacement in Cyprus
When Desdemona hears the news that she will be leaving Cyprus, she expresses her happiness.
"Oh. Thank the dear gods. We finally get to go home!" Desdemona cried.
"Are you mad, woman?"
Othello then hits Desdemona.
"You devil!" cried Othello.
Desdemona then leaves. Lodovico is horrified by Othello's loss of self-control, and asks Othello to call back Desdemona, who has left.
"Desdemona, come back."
"Yes, honey?"
Othello then turns to Lodovico. "What would you do with her?"
"Excuse me. But what are you talking about?"
"She-She….She is false! Why she does not only love me! I will obey the Duke's orders, I will go back to Venice. Out…Out of here Desdemona!"
Lodovico is shocked. He is shocked that Othello, a good, self-controlled man, lose control of himself.
Lodovico then thinks to himself, 'I wonder…..has he gone mad?'
Iago refuses to answer the question, knowing what Lodovico is thinking. He tells him that he must see for himself.