The film closely follows the plot of the play, but restructures and reorders individual scenes. Welles trimmed the source material, which is generally around three hours when performed, to a little over 90 minutes for the film. The opening funeral scene is not in the original play.[4]
The movie opens with Othello and Desdemona's funeral.
The first main scene shows Iago's complaining to Roderigo about not being advised of the marriage between Othello and Desdemona. Roderigo is contemplating killing himself but Iago says “Ere I would say I would drown myself for the love of a guinea hen, I would change my humanity with a baboon,” meaning Iago would rather be a baboon than kill himself over a woman. Iago further says "Put but money in thy purse" and urges Roderigo to sell all his lands and give the money to Iago, who will use it to convince Desdemona to have sex.
Desdemona's father Brabantio is furious about the marriage after being told of it by Iago and Roderigo. Brabantio accuses Othello of bewitching his daughter. Othello convinces Brabantio that it was not witchcraft but rather by his tragic tales.
By planting a handkerchief, Iago convinces Othello that Desdemona is having an affair with Cassio. Othello previously promoted Cassio to lieutenant over Iago, hence Iago's jealousy.
Othello strangles Desdemona. Iago knifes Emilia to death as she protests Desdemona's innocence. Othello realises his mistake.
