In order to get a promotion at work, Stan has to convince the dictator of Isla Island to sign a treaty. Stan meets the general and accidentally kills him and has Roger pose as the leader of the small island nation. Meanwhile, Steve and Snot become competitive to see who can get farther with the other’s mom.

When Lois finds a lump on her breast, she goes to the doctor to test for cancer. The tests come back benign, but the doctor looks at her family medical history and reveals some news about Lois' heritage.

Don decides to include Betty on a company business trip. Pete lends a hand to a neighbor in his apartment building.

Mrs Krabappel is fired from Springfield Elementary after Bart spikes her coffee, causing her to make a drunken fool of herself. She is replaced by a cool new teacher, Mr. Vaughn, who is a quick hit with the kids. Bart, however, struggles with the guilt and considers telling Principal Skinner the truth.