With the latest quiz show craze sweeping the nation, television executives inform Krusty that his show’s ratings have taken a nosedive. The network pushes the clown to take chances and push the envelope. But things go too far when executives demand changes during a live broadcast. Krusty tells his audience that the upcoming Friday show will be his last. During an interview with newscaster Kent Brockman, Krusty reveals that the first ten years of his show were accidentally erased. Sideshow Bob watches the interview on television from inside his prison cell. He realizes that all of his work on the show has been wiped out…and vows to “erase” Krusty’s future. Later, Sideshow Bob is paroled from prison. He makes his way to a storage warehouse, where he takes up room inside a locker. Donning a suit, Bob puts his scheme for revenge in motion. He interviews for the position of assistant janitor at Springfield Elementary, where Skinner auditions him for the task of reading the school’s morning announcements. Skinner is greatly impressed and hires him.

While reading the morning announcements, Sideshow Bob tricks Bart into entering a deserted shed on school property. There, Bart is tied to a chair with rope. Using a book on hypnosis, Bob brainwashes Bart and plants a scheme to kill Krusty in the boy’s head. Bart returns home in a zombie-like state, but the family does not sense something is amiss. Later, Sideshow Bob instructs Bart to smash a Krusty statue with a baseball bat. They boy eagerly complies. With the last of the tests now complete, Sideshow Bob congratulates Bart and hands him a diploma.

An audience gathers at Krustylu Studios to watch Krusty’s farewell broadcast. Amongst those in attendance are the Simpsons. Meanwhile, Sideshow Bob sneaks into the studio unnoticed. He pours plastic explosive into a tube around Bart’s waist and attaches metallic detonators to his palms. Sideshow tells Bart that when Krusty says the line,“ I’ve never had such a great audience,” he is to run up and hug his idol…blowing them both to Kingdom Come. After Bart takes his seat in the audience, Sideshow Bob makes his way to the catwalks high above, the perfect vantage point to watch his insidious plot unfold. A short time later, Krusty utters the trigger phrase. Bart rises from his seat and heads for the stage. But before Bart completes his mission, Krusty apologizes for mistreating Sideshow Bob and driving him to a life of crime. A tear rolls from Bob’s eye. Suddenly, Bob has a change of heart about carrying out the plot. He bursts onstage and yells out a warning, but his plea is drowned out by the audience. Luckily, Mr. Teeny puts two and two together. He swings down from the rafters, grabs Bart’s explosive belt and hurls it into the Green Room, which is filled with network executives. The bomb detonates…creating a hellish super-executive creature. Later, Krusty announces that he has changed his mind and is no longer retiring. He then chooses the greatest sidekick he’s ever known…Sideshow Mel. Sideshow Bob is once again filled with murderous rage.