Background: The military prowess of Otello, a former slave from Africa, led him to being promoted to Commander of the Venetian Republic. He secretly married the young, self-confident Desdemona, against her father’s wishes, and took her to the highly contested island of Cyprus.
Act 1 Otello returns to Cyprus after the Turkish fleet became scattered in a raging storm. The only people not glad to see him are Iago and Roderigo. Iago was due for promotion, but was passed over and Cassio named captain instead. The merchant Rodrigo's in love with Desdemona. Iago and Roderigo hatch a plot. Cassio, drunk, becomes embroiled in a fight with Montano, the former governor of Cyprus. Otello intervenes and demotes Cassio on the spot. Desdemona tries to calm and support her husband.
Act 2 Iago continues with his infernal plan to destroy Otello. He tells Cassio to ask Desdemona to persuade Otello to pardon him. Iago manages to sow seeds of jealousy in Otello’s mind, making him begin suspecting Desdemona of being unfaithful. The people worship Desdemona like a Madonna. She asks Otello to pardon Cassio, fanning the flames of his jealousy. Iago steals Otello's first love token to Desdemona, a handkerchief, and plants it in Cassio’s house. Otello demands proof of her infidelity. Iago says he heard Cassio talking of his love for Desdemona in his sleep and that he thought he saw him holding her handkerchief the day before. Otello wants revenge.
Act 3 Otello’s rage and mistrust intensify when Desdemona again asks him to pardon Cassio. He wants to see the handkerchief but she doesn't have it with her. Otello calls her a whore. Iago tells Otello to hide. Cassio arrives, hoping for news from Desdemona about whether Otello might pardon him, but finds Iago instead. During their conversation Cassio produces a handkerchief which he found in his house. Otello, who only heard part of their conversation, saw everything. Lodovico, brings news from Venice: Otello's been recalled and Cassio named as his successor. Otello loses all composure and humiliates Desdemona in public. While the Venetian delegation and people express their outrage and sadness, Iago siezes the chance to ensure that his plan runs its course. He tells Otello to kill his wife tonight, because they're supposed to leave for Venice the next day, and that he'll arrange for Cassio to be got rid of, so that Otello will have to remain in Cyprus. Thoughts of Desdemona’s infidelity and punishment drive Otello almost insane and he collapses. Iago feels victorious.
Act 4 Desdemona, filled with premonitions of death, seeks comfort in prayer. She's waiting for her husband. Otello comes to his wife, surprising her with tender endearments. He confronts her about her affair with Cassio. Desdemona’s protestations of innocence are to no avail - Otello kills her. Horrified by Desdemona’s murder, Emilia exposes her husband Iago’s machinations. Iago flees. Roderigo was killed while trying to carry out Iago’s order to murder Cassio. Otello lies beside Desdemona’s body. Life, as we know it, has ceased to exist for him.