This scene starts with Iago and Roderigo arguing, as Roderigo believes that Iago is loyal to Othello, the man who Roderigo despises because Othello married Desdemona, the lady who Roderigo loves. Iago convinces him that he also hates Othello, And so they go to Brabantio's home, who is Desdemona's father, and tell him about his daughter and the Moor's marriage. Brabantio is angry, as Othello is not of high nobility, and is a black man.
ACT 2- SCENE 3
Iago warns Othello of Brabntio. Othello sees some men approaching and gets ready to fight, but it is only Michael Cassio and his men who are telling Othello that the Duke of Venice is calling him about the matter in Cyprus. Then Brabantio comes, but Othello tells him he has been called by the Duke. Brabantio goes with him and tells the Duke of their situation. The Duke does not see anything wrong with the situation, and approves the marriage. However, he send Othello to fight the Turkish.
ACT 3- SCENE 1 AND 2
The Turks have drowned, and now, Othello returns back to Venice, where Desdemona is. Cassio takes her hand to tell her about Othello's return. Iago sees this and decides to turn it in his favour and say that Desdemona is cheating on Othello with Cassio. Othello returns. There is feast and everyone but Roderigo and Iago go. Iago tells Roderigo to start a fight with Cassio about this, and it will drive Othello to be mad and unhappy, therefore making Desdemona leave him.
ACT 3- SCENE 3 AND 4
Cassio is guarding and Iago comes up to him and offers him a drink. Cassio refuses but then drinks anyway. As Cassio leaves to get the celebrators, Iago tells Montano that Cassio has a lot of responsibility for being an alcoholic. Meanwhile, Cassio is chasing Roderigo and Montano steps in, but Cassio stabs him.Othello wants to know what happened so Iago 'reluctantly' tells him. Othello dismisses Cassio. Desdemona wakes up and Othello leads her back to bed. Iago tells Cassio to appeal to Desdemona so that Othello forgives him.Cassio leaves and Rodrigo enters and confronts Iago for taking all his money on winning over Desdemona. Iago assures him that everything is going to plan (it isn't).
Cassio, in order to please Othello, sends musicians in front of Othello's window. Othello tells his clown to make them go away.Cassio asks the town to tell Emilia that he must speak to Desdemona. Emilia tells Cassio that Desdemona has pleaded for him to Othello but, Montano is very important and Othello can't be on Cassio's side. Emilia tells Cassio to wait and she shall bring Desdemona. Othello gives Iago some letters to deliver.
Cassio and Desdemona are speaking. Othello and Iago enter; Cassio leaves.Iago says that this is because he and Desdemona are having an affair. Othello says he has a headache and Desdemona offers to bind his head with the handkerchief. It falls to the ground as he pushes it away. Iago takes it and decides to put it in Cassio's room. Before he can, Othello demands for visual proof that Cassio and Desdemona slept together. Iago has none but says that when he and Cassio were living together, Cassio said Desdemona's name in his sleep and kissed Iago thinking he was Desdemona. Othello then confronts Desdemona and asks for the handkerchief and tells the story of how he got it. She says it is not with her now. Cassio helps Desdemona by making his prostitute sew another one just like that.