Bart and Milhouse are thrilled to hear that a film version of their favorite comic book series, Radioactive Man, is in production. Rainier Wolfcastle, the star of the McBain films, is chosen to play Radioactive Man, after the studio heads reject the idea of using Dirk Richter, the star of the now-maligned 1970's Radioactive Man TV series, mainly because Richter is 70 years old and also dead. Even more exciting for the Springfield Elementary School children, the production moves to their town after the executives sees an ad for Springfields movie production scene, mistaking its small size and poor spelling (Flim Springfield) as a sign that it doesn't need to advertise itself. A search is launched for a young actor to play Radioactive Man's sidekick Fallout Boy, and Bart auditions. Bart does well, but is rejected because he is an inch too short. Despite Bart manages to grow an extra half inch in one day after subjecting himself to several methods of stretching his limbs, Milhouse gets the part, albeit reluctantly, under pressure from his greedy parents.
A despondent Bart is told by Lisa that he is still needed as Milhouse's friend and confidant, and Bart eagerly accepts this new role. However, Milhouse finds his own job intolerable, especially his hate for the constant need to reshoot the same scene over and over again, as well as the rigorous makeup routine. Eventually, Milhouse goes missing, right during the filming of the most expensive scene in the movie, where he was supposed to save Radioactive Man from an oncoming flood of acid. Unable to escape on his own, Rainier Wolfcastle is swept away by the acid, though he survives with minor burns and a dissolved costume. The film is suspended while the townspeople search for Milhouse. Eventually Bart finds him in the tree house, and despite encouragement from former child star Mickey Rooney, Milhouse gives up on his acting career. Mickey Rooney tried to take over as Fallout Boy; however, all production on the film is aborted, with the project bankrupt, thanks to price gouging and other unscrupulous conduct by the people of Springfield. Despite Rooney's stern lecture about their greed, Mayor Quimby insists the townspeople can not give any of the directors' money back to them, so with their film cancelled, the directors return to Hollywood — "where people treat each other right".