When Marge sees Bart and Milhouse incited to violence after watching an episode of South Park, she tries to turn them onto some good television on the PAX television network. They run out of the room and find themselves outside and bored. After tying a thread to a housefly, that lands itself inside of the Flanders home, Bart and Milhouse find themselves inside the home, unsupervised. They cause some damage and find Ned's collection of Beatles memorabilia. They drink from cans of a 40-year-old novelty beverage and start to get sick. Ned and the boys return to their home to find the house "slightly askew," and they flee to their panic room and call the police. The police arrive and capture the boys and Bart pleads that his parents not be called. The parents are called and as part of Bart's punishment he is sentenced to spending all his time under the supervision of a parent. He is also no longer allowed to play with Milhouse, who Marge believes incites Bart into his bad behavior. Bart joins the "Pre-Teen Braves" and Homer becomes the tribe leader. When Homer fails in his leadership skills, Marge takes over. Marge takes the boys on a nature walk and they meet a Native American who shows them a field that is in need of restoration. The "Pre-Teen Braves" return to the field to begin their clean-up effort, only to discover that the "Calvary Kids" that Milhouse and his father are a members of have already done the job. The two groups go to war and try to outdo each other in doing good. When the opportunity to become batboys at an Isotopes game is on the line, the two sides redouble their efforts for their candy sales. The "Pre-Teen Braves" lace the "Calvary Kids" candy bars with laxatives and believe they are going to win. Only the senior citizens, in a need of relief from constipation, buy the "Calvary Kids" a win. At the Isotopes game, the "Calvary Kids" are delayed from arriving and the "Pre-Teen Braves" take their place singing their version of the national anthem. The crowd becomes angered by the version of the anthem that is being sung and when the real "Calvary Kids" arrive, a fight breaks out between everyone in the crowd. When the image of Marge crying is shown on the Jumbotron, the fighting ends and the sweet soothing hymn of the national anthem of Canada is sung by all present. In the end, Bart and Milhouse sum it up by saying that they've learned that: "War is not the answer--except to all of America's problems."
Elenco: Dan Castellaneta , Julie Kavner , Nancy Cartwright , Yeardley Smith , Hank Azaria , Harry Shearer .