Iago and Roderigo go to see Senator Brabantio at his home and ‘rouse him’ in the middle of the night. Iago stays hidden but gets Roderigo to tell Brabantio that Desdemona has secretly married the General of the army, Othello. They call Othello a ‘knave of common hire’ and a ‘lascivious Moor’. At the end of the scene Roderigo promises to find Othello and help Brabantio ‘apprehend her and the Moor’.

Iago tells Othello that Brabantio knows about his secret marriage to Desdemona and warns him that Brabantio will try to end it, but Othello says ‘Let him do his spite’. Cassio arrives with a message ordering Othello to go to the Senate to talk about the war with the Turks.

Brabantio arrives with Roderigo to arrest Othello, calling him a ‘foul thief’ and asking ‘where hast thou stowed my daughter?’

Brabantio goes to the Senate with Othello. He tells the Duke of Venice that he believes Othello has stolen his daughter using ‘witchcraft’. Othello and Desdemona both explain how they fell in love and the Duke is satisfied there's no wrongdoing. He then sends Othello and the army to Cyprus to fight the Turks and Desdemona asks to go with them. As they leave Brabantio warns Othello to watch Desdemona saying ‘she has deceived her Father, and may thee’. Iago tells Roderigo to follow the army to Cyprus to help him get revenge on Othello.

Iago tells the audience his plan is to make Othello jealous of Cassio in his first soliloquy. He thinks this will be possible and that he will be believed because Othello ‘thinks men honest but that seem to be so’.

Everyone arrives in Cyprus and Iago notices Cassio being friendly to Desdemona and kissing her. He decides to use this against him. After travelling separately, Othello is delighted to see Desdemona again, calling her ‘my fair warrior’. Iago convinces Roderigo to pick a fight with Cassio to get him into trouble.

In a second soliloquy, Iago tells the audience that he plans to get revenge by making Othello so jealous ‘that judgement cannot cure’ it.

There is a party to celebrate the defeat of the Turkish ships and Iago convinces Cassio to drink more than he is used to. As instructed by Iago, Roderigo provokes Cassio to fight and Cassio ends up injuring Montano who tries to stop them. Othello fires Cassio as his lieutenant. Iago tells Cassio to ask Desdemona for help in getting his job back. Cassio thinks Iago is a good friend and says ‘You advise me well’.

In another soliloquy, Iago tells the audience that his plan is going well. He says about Desdemona that he will ‘turn her virtue into pitch’ and ‘make the net that shall enmesh them all’.

Iago suggests to Othello that Cassio and Desdemona are having an affair but Othello doesn’t believe it at first, saying ‘I’ll see before I doubt, when I doubt, prove’. However, he begins to accept that Iago could be telling the truth when Desdemona asks him to forgive Cassio.

Othello complains that his head hurts and Desdemona tries to help him. She drops her handkerchief (a gift from Othello) and Iago's wife, Emilia, picks it up and gives it to Iago.

In his fourth soliloquy, Iago tells the audience that he will plant Desdemona’s handkerchief in Cassio’s room, to give Othello proof that there is something happening between them. He says ‘This may do something. / The Moor already changes with my poison’.

Othello demands ‘ocular proof’ of his wife’s affair with Cassio. Iago pretends that he has heard Cassio talking in his sleep about the affair, then adds that he has seen Cassio using Desdemona’s handkerchief. Othello is convinced and he asks Iago to kill Cassio and plans to kill Desdemona himself, crying ‘Damn her, lewd minx!’

Desdemona asks Othello to forgive Cassio again. Othello tries to make her confess to giving away the handkerchief but she doesn’t. He storms off and Emilia suggests that he is jealous but Desdemona says, ‘I never gave him cause’.

Bianca, who is in love with Cassio, complains to Cassio that he has not been to see her. He gives her Desdemona’s handkerchief, saying that he found it in his room.

Othello becomes so wound up about the affair he thinks is happening, he falls down in a fit. Iago tells him to hide and listen as he talks to Cassio about Desdemona but Iago actually talks to Cassio about Bianca instead. Othello hears everything and sees Bianca arrive to give Cassio the handkerchief back.

Desdemona brings Lodovico, a messenger from Venice, to see Othello. Othello is so wound up about what he has seen and heard that he hits Desdemona and insults her in front of everyone. Lodovico can’t believe the way he is acting and asks ‘Is this the noble Moor… / whom passion could not shake?’

Othello sends Emilia to fetch Desdemona and Desdemona explains that she has no idea why he is angry. Desdemona then asks Iago why Othello is behaving in this way and he tells her ‘all things shall be well’.

Roderigo challenges Iago, saying ‘I do not find that thou deal’st justly with me’, but Iago convinces him that he must kill Cassio in order to stop Othello and Desdemona leaving Cyprus.

Emilia helps Desdemona to get ready for bed. Emilia is worried about Othello’s behaviour but Desdemona remains loyal to him and sings a song of 'willow' that she can't get out of her head. Emilia blames men for not understanding that women have feelings just as they do and adds ‘The ills we do, their ills instruct us so’.

Roderigo attacks Cassio and is wounded by him. Seeing this, Iago stabs Cassio in the leg from behind and runs away. Othello hears Cassio’s yells and believes Iago has kept his word to kill Cassio. He then goes to kill Desdemona in her bed. As others run to Cassio’s aid, Iago returns and pretends to be horrified , yelling ‘O murderous slave! O villain!’ at Roderigo and killing him.

Desdemona is asleep on her bed. Othello accuses her directly of an affair with Cassio but he doesn’t believe her when she tells him she is innocent. She pleads with him ‘O banish me, my lord, but kill me not!’ and he suffocates her.

Emilia arrives and hears Desdemona calling out as she dies ‘O falsely, falsely murdered!’. Othello says he killed her because of her affair with Cassio and that ‘Thy husband knew it all’. Emilia yells for help and Montano, Iago and others rush in.

Emilia admits that she gave the handkerchief to Iago and blames him for everything that has happened. Iago stabs her and runs away. As she dies, Emilia says ‘Moor, she was chaste. She loved thee, cruel Moor’.

Lodovico, Cassio, Montano and others chase after Iago and bring him back as a prisoner. Othello tries to kill Iago but only wounds him. He then says ‘Nought I did in hate but all in honour’, stabs himself, kisses Desdemona and dies.