Othello is the general, and made Cassio his lieutenant. Iago is jealous because he wants to be the lieutenant.
How can I get Othello to make me his lieutenant?
Iago gets Cassio drunk and uses Roderigo to get him to fight.
This is working perfectly, I just got to act surprised.
Montano steps in to break up the fight, then Cassio stabs him. Othello comes in and removes Cassio from being lieutenant. Cassios reputation is ruined.
Othello still doesn't make Iago lieutenant so to get him out of the way he leads him to think Cassio and his wife Desdemona are lovers. But they actually are not.
Can this be? She did decieve her father...
Desdemona loses the handkerchief that was Othellos first gift to her. She tells him it is not lost and bickers at him to go talk to Cassio which makes Othello think they are lovers because Iago said he saw it with Cassio. Meaning she was with him and left it there. Othello is so upset he leaves.
Othello had dreams about Desdemona and Cassio which upset him even more, in the early morning he left to the ocean. Iago followed him. they talked then Othello grabbed Iago and told him that if it was true he would kill desdimona.