Bart buys an extravagant belt on a trip to the mall, but the school bullies beat him up and steal it. When Homer goes to confront the parents of the boys in Moe's Tavern he promptly receives a beating of his own. During the beating, however, Homer remains completely unfazed; Moe sees this and proposes to Homer that he test out his abilities in boxing.
In a store, the Simpsons family look around for things they want to buy. While there, Comic Book Guy could not return his small-sized gimmicky belt because he does not have his proof of purchase. Bart obtains it from him for $4. He shows off its features to his classmates, but is then chased and beaten by the Springfield Elementary bullies, who steal his belt. In response, Homer meets with the bullies' parents at Moe's Tavern but is also beaten. Despite the force used against Homer, he does not fall down (explained by Dr. Hibbert as an ability gained from a genetic defect). Moe is impressed enough to reveal that he used to be a boxer, and agrees to coach Homer. There is one problem - Homer's punches are especially weak - so Moe decides that Homer should wait for his opponents to get exhausted from pummeling him, then push them over.
Homer does well, mostly facing underfed Hobo opponents who cannot force him to fall. Eventually Lucius Sweet, Moe's former boxing manager, arrives with a proposition for Moe; the two arrange a match between Homer and the powerful boxing champion Drederick Tatum (a Mike Tyson parody), in a massive star-studded event. Despite a promise to Marge to stop the fight if Homer's life is endangered, Moe is prepared to have Homer endure three rounds. Just seconds into the fight, it becomes clear that Tatum is brutal and inexhaustible, meaning that Homer is going to get killed. Homer realizes the original plan is not going to work, and decides to punch his opponent, but misses. Just as Tatum is about to strike a possibly fatal blow, Moe airlifts the badly-beaten Homer from the ring using Fan Man's paramotor. During the credits, Moe, still with the para-motor, is shown saving people from natural disasters in different countries.