While working as Krusty the Clown's personal assistant, Bart accidentally steals the limelight when he knocks over a set on live TV and says four magic words: "I didn't do it." Bart becomes more famous than anyone, especially Krusty, could have ever expected, landing his own TV series, cutting a record, appearing on Late Night with Conan O'Brien and on T-shirts from Springfield to Shelbyville. Bart's fame comes to an end when his fans turn fickle and realize that "I didn't do it" isn't such a funny catchphrase after all.