Bart's class visits the box factory, where the tour bores the children to tears. Next door to the factory is Krusty's TV studio; so Bart sneaks away from the tour and goes to the studio. Principal Skinner calls Homer to tell him that Bart is missing. When Bart brings Krusty a danish…Krusty hires him as his assistant. He goes home and tells the family about his new job. Krusty soon starts working him to death. Just as he is about to quit, Krusty tells him that he needs him to be on the show. Bart screws up his line and says, "I didn't do it." The audience just loves it and it becomes Bart's catch phrase. He soon records an album and has a chat line. Lisa makes Bart realize that his fame is just an obnoxious fad. Bart is going to be on Late Night with Conan O'Brien, so he practices some intelligent conversation to be more multi-dimensional. When that does not work, he embraces his identity. On the next show, he finds that his catch phrase has worn out and his fame is over.