Act 1 opens with Iago and Roderigo on a street in Venice, Italy. Iago and Roderigo were fighting about how Roderigo has been giving Iago money under the impression that Iago was giving gifts to Desdemona (Roderigo's love interest). But Roderigo has discovered that Desdemona has eloped with a moor named Othello. Iago discovers that Othello has promoted Michael Cassio to Lieutenant instead of himself. Iago then formulates a plane where he will be promoted by Othello instead of Michael Cassio and Roderigo will get Desdemona. They then proceed to wake up Brabantio by yelling "thief" and informing him that Othello had stolen his daughter, Desdemona. Brabantio ,in disbelief, goes to check for her and when finding that she is not in her room he goes to arrest Othello for drugging or using black magic to get Desdemona to marry him.
Othello had been called by the Duke to discuss and urgent military problem that is involved with Cyprus (an island Venice controls). Brabantio decides to go with Othello to the meeting to see what the Duke and his acquaintances think of the marriage between Desdemona and Othello. The Duke of Venice was discussing the Turkish attack on Cyprus after seeing through a plot which would have distracted the Venetians from an attack on Cyprus. Then Othello and Brabantio enter and begin to discuss Brabantio's problem with Othello "stealing" his daughter. To prove that Desdemona loves him he sends someone to get her. She proceeds to tell everyone that she fell in love with Othello of her own accord. After hearing this Brabantio leaves and the Duke sends Othello and with some reluctance Desdemona to Cyprus.
Act 2 opens with a storm which broke the Turkish fleet heading towards Cyprus. Though this is good news for the Venetians and the people of Cyprus, Othello's ship still hadn't arrived at Cyprus. Cassio had arrived first and then Iago, Desdemona and Emilia (Iago's wife and Desdemona's helper). Othello finally arrives and is welcomed by his loving wife. Later on Othello is informed that the Turks will not be attacking. Othello decides to throw a celebration because of their victory and also to celebrate his recent marriage which he hasn't had time to celebrate.
Iago is standing guard with Cassio at the celebration. Iago has been scheming and has come up with an idea to get Cassio relieved of duty. He's decided to get Cassio drunk, fully knowing that Cassio cannot hold his liquor. He then would get Roderigo to fight Cassio in front of Montano which will get Cassio fired. Iago's plan works well and while Cassio is chasing Roderigo and then Montano tries to break them up. Instead of stopping hem from fighting Montano gets injured by Cassio. All this commotion wakes up Othello who goes down to see what is going on. He asks Montano what had happened and Iago fills in the blanks, leaving out his part in the fight and Michael Cassio gets stripped of his job of lieutenant. When Othello and everyone else leaves Iago persuades Cassio to go ask Desdemona to help him.
in an attempt to impress Othello to regain his job, Cassio pays ,musicians to play outside Othello''s window. Othello hears the music and sends down a clown?servant to ask them to go away. Cassio then asks the clown to go and see if Desdemona is willing to talk to him. At this moment Iago walks in and tells Cassio he will get Emilia to fetch Desdemona right away. Emilia comes out to take Cassio to see Desdemona about about her helping him to get his reputation and job back. Desdemona agrees to help Cassio and she vows to convince her husband to reinstate Cassio as lieutenant. Cassio leaves as he sees Othello enter because he didn't want to confront Othello as he is ashamed of himself. Desdemona starts discussing Cassio's case with Othello and she becomes more insistent about Cassio and his job. Othello, who is not to happy about this agrees to try.
Iago plants the idea of Desdemona having an affair with Cassio in Othello's head. As Othello begins to doubt her Iago makes up a story in which Cassio is sleep talking about his love for Desdemona. Iago knows that Emilia had found Desdemona's handkerchief, he requested Emilia to give it to him and he placed it in Cassio's room. He mentioned the handkerchief to Othello. Now suspicious Othello confronts Desdemona about it. She admits that she does not have the handkerchief which enrages Othello and he leaves. Then Cassio and Iago enter the room, they discuss Othello's behaviour and Iago goes to "comfort" Othello. Othello swears to Iago that Cassio will be dead and that he will take revenge upon his wife. (Not knowing of the handkerchiefs owner) Cassio asked a lady called Bianca to make a copy of it.