In celebration of the last day of school, Bart wakes up the family by banging pots and pans together. Even though Homer initially says that he has a plan of making Bart go to summer camp, Marge points out it is a prison road crew in the picture. Bart interjects that he did that last summer, and he is not allowed back. The family convenes in the kitchen, where Homer discovers, while reading the local newspaper, that the Fourth of July fireworks has been cancelled, due to the fact that the city is broke. Meanwhile, Springfield Elementary has their annual Field Day festivities, where kids learn to balance eggs on spatulas and have their ankles tied to someone who does not care two cents about them. The race around the school prompts everyone to do their best, including Milhouse, who has been practising for this race. Milhouse reveals to Bart he has been training, but Martin overhears this secret. Martin then wagers his money on Milhouse to win, potentially bankrupting the bullies because of the tremendously long odds against Milhouse.
As each student runs during the race, Milhouse leads the pack before Nelson and the bullies plan to knock some sense out of him. When Nelson awaits for Milhouse at the pivotal turn of the race, he hands Milhouse a cup of water before hitting him. Bart sees this, but runs ahead of the race to win first place. After Bart receives a blue ribbon for first place, Milhouse emerges from the bushes, conveniently with amnesia. Although Bart has several chances to disclose to Milhouse what happened during the race, Bart lets the opportunities slip, even at a town ceremony honoring his victory. However, when one of the bullies slingshots at Milhouse's forehead, the memories come rushing back, with Milhouse remembering how Bart just stood idly by as Milhouse suffered beating after beating.
The outraged townspeople chase Bart from the ceremony. Bart runs to the retirement home, to seek help from Grandpa, without much luck. Meanwhile, elsewhere, Homer finds a man from the past to execute a spectacular fireworks display (set to "Sometimes When We Touch") for the town, but a fight breaks out between them. The fireworks go awry, yet Bart quickly thinks on his feet to get the town to believe that Milhouse is the modest hero.