When a new, tough-looking kid at school named Donny teams up with Bart to help him carry out his pranks, Bart thinks he has found his ultimate partner in crime. However, when Bart's seemingly foolproof pranks begin to backfire, Groundskeeper Willie warns Bart that he smells a rat in Bart's group of friends. With Principal Skinner on his case and the possibility of expulsion on the horizon, Bart must figure out who he can trust and who he must get rid of before it is too late. Meanwhile, Homer receives a fancy loaner car after Marge damages their old car in an accident, and he grows extremely attached to his new set of luxury wheels.

When Lisa convinces Marge to pursue her childhood dream of becoming a ballerina by auditioning for the Chazz Busby Ballet Academy, Chazz discovers Lisa's natural talent and enrolls her in the academy instead. During a break from practice, Lisa inhales her fellow ballerinas' cigarette smoke and attributes her improvement in ballet to smoking. Lisa soon becomes addicted to secondhand smoke, with no chance of quitting in sight. Meanwhile, Homer shows Bart his secret room where he manufactures beef jerky. When Homer realizes that a family of raccoons have made off with his beef, he decides to confront the animals.