Bart is believed to be a genius after he switches I.Q. tests with brainy Martin Prince.
As the Simpsons play a game of Scrabble, Lisa reminds Bart that he should be developing verbal abilities for his aptitude test. Later, Principal Skinner catches Bart spraying graffiti on the school. During the intelligence test, Bart imagines himself the literal victim of a difficult math question. Faced with the prospect of flunking the school’s intelligence test, Bart switches exams with brainy Martin Prince. When school psychologist Dr. Pryor studies the results, he is shocked and pleased to learn that Bart is a genius. Upon Dr. Pryor’s suggestion, Homer and Marge agree to place Bart into a school where students learn at their own pace and are unencumbered by grades.
Bart’s first day at his new school leaves him feeling greatly misplaced, as the other students show advanced academic skills. Even though Bart feels out of place at school, he enjoys the newfound attention Homer shows toward him. Marge buys tickets to the opera hoping to stimulate her son with a little culture. But Homer and Bart join forces to ridicule the performance and make rude noises.
Outcast by his genius classmates, Bart visits his old school, but he is rejected by his friends and labeled a “poindexter.” When Bart’s science project blows up and nearly destroys the school, he decides to return to being stupid. Bart confesses to Dr. Pryor that Martin Prince is really a genius and not him. When Bart returns home with his clothes ruined by his science accident, Homer assures the boy that every genius has his bad days. Bart confesses to Homer that he switched tests with a real genius, and although it was a stupid thing to do, he is glad that it at least brought them closer together. An irate Homer chases the boy through the house.
Source: 20th Century Fox