The play begins in Venice with Roderigo a nobleman and Iago arguing in the middle of a street. To help Iago obtain Desdemona's hand in marriage, Roderigo has given him a significant amount of money. However, he recently found out that Othello, the Moorish (North African) commander that Iago serves, and Desdemona have eloped. Iago reassures Roderigo that he despises Othello and tells him that Othello recently rejected his candidature for lieutenant, even though he was Othello's ancient and had the endorsements of three influential Venetians. Rather of promoting someone who, in Iago's opinion is only a theoretical military theory with no experience commanding or fighting soldiers, Othello chose to elevate Michael Cassio. Iago uses Roderigo as a tool to incite Desdemona's family to turn against Othello, collectively they trick Brabanito, Desdemona's father into thinking she has been kidnapped. Brabanito becomes infuriated with Iago's harsh comments regarding Othello and Desdemona's intimacy, which prompts him to look for his daughter. Iago leaves Roderigo to serve Othello once his plan is put into action, which infuriates Brabanito and makes him want to revenge. 

Iago notifies Othello of Roderigo's derogatory remarks at the inn and alerts him about Brabanito's plan to compel a divorce. Unfazed, Othello demands to face the oncoming  group directly, reaffirming his innocence and love for Desdemona. Othello maintains his composure and advises both sides to be ready for battle when Brabanito and his soldiers show up. When he discloses that the Duke has summoned him, Brabanito comes to join him in bringing his grievance before the Duke. 

After talking about the Turkish danger to Cyprus, the Duke and his senators are interrupted by news that the Turks have redirected their soldiers to Rhodes and are now preparing to return to Cyprus with a larger force. During all of this, Brabanito accuses Othello of enticing his daughter Desdemona. The Duke gives Othello the chance to defend himself, despite his initial dominance. By narrating how Desdemona was enthralled by his life story, Othello rejects the theory of using magic to woo Desdemona. Following in the footsteps of her mother, Desdemona declares her intention of marrying Othello and places her husbands loyalty above her fathers. Desdemona refuses to stay with her father despite suggestions that she should do so, instead she goes with Othello to Cyprus to help him fight. Iago comforts Roderigo who is upset at losing Desdemona, and urges him to travel with them to Cyprus. Iago takes advantage of the situation and creates a plan to influence Othello by fabricating a love triangle between Desdemona and Cassio.

In Othello’s Act five’s terrible climax plays out with growing suspense and hopelessness. When Iago tricks Othello into thinking that Desdemona has cheated on Cassio, it is the height of his betrayal. Othello attacks Desdemona out of jealously and in a fit of rage suffocates her. The scene is set up for a dramatic revelation of the truth when Emilia, Iago’s wife and Desdemona’s attendant, arrives and reveals her husbands betrayal. Othello is overcome with regret and guilt after realising the magnitude of his error. He commits suicide in a tragic last act. Although Iago’s villainy is revealed in the plays conclusion and he is subsequently arrested, the terrible effects of his deception cannot be undone.