Othello is a tale of jealousy and revenge. The play takes place in Venice as two friends, Roderigo, and Iago, are arguing. Iago has unfortunate news: Desdemona, a woman Roderigo hoped to marry, has already been married to Othello, a Venetian general. The audience soon learns that Iago has a personal grievance against Othello: he has promoted a younger man, Cassio, to be his lieutenant, passing over Iago.
The two men decide to go to Desdemona’s father, Barbanzio, and tell him that she was stolen and married to Othello, who is a Moor. Her father finds that she is indeed missing, and Iago decides to rush back to Othello before he is seen at Barbanzio's house.
At his lodgings, Othello receives a message from the Duke; there has been a Turkish invasion in Cyprus and Othello’s help is urgently needed. Before Othello can leave, Barbanzio comes in and accuses the Moor of stealing his daughter through witchcraft. When Othello says he is on his way to see the Duke, Barbanzio goes along to accuse Othello of these crimes in front of the Senate.
At the Senate, Othello explains his case, and Desdemona herself comes to sayshe willingly married Othello. Her father concedes, knowing he lost his battle, and Othello makes ready to depart for Cyprus.
The next day, Cassio, Roderigo, Desdemona, and Iago land in Cyprus.Tthey await Othello’s ship. The audience learns that the night before, there was a great storm, and there are reports that all the Turkish ships were wrecked at sea. When Cassio greets Desdemona, he holds her hand and, in an aside to the audience, Iago states that he will use this to entangle Cassio. When Othello arrives, he declares that there will be a great celebration because Cyprus is safe. Meanwhile, Iago plans to help his friend (Roderigo) by breaking up Desdemona’s marriage. First, he gets Cassio drunk, and sends Roderigo to fight with him. A brawl results and afterwards, Cassio is stripped of his rank.
This does not stop Iago from trying to ruin Othello’s marriage. He again tells the audience that he will try to frame Cassio and Desdemona as lovers to make Othello jealous. Cassio then goes to Desdemona to ask her to speak to Othello on his behalf. When Othello enters the room, Cassio quickly leaves looking very guilty. Iago seizes the opportunity to convince Othello that Desdemona is having an affair with Cassio. He succeeds, and Othello becomes increasingly jealous.
Iago devises a plan to get Cassio in the room while Othello is in earshot, and states that he will get him to confess to the affair. Cassio enters with Iago, who had just been speaking to him about his lover Bianca. To Othello, it appears Cassio is admitting to an affair with Desdemona. For the rest of the play, Iago weaves a stream of lies that infects everyone.
These lies lead to the deaths of Emilia (Iago's wife), and Roderigo. Othello ends up killing Desdemona in a jealous rage, and then himself when he learns the truth of her innocence. In Iago is found out, and, unrepentant, is imprisoned.