Homer learns that the retiring co-safety inspector of Sector 7G Don Bookner has been covering for him for years, which means Homer will actually have to work from now on. He is put under pressure and is unable to take a break. Marge suggests that the family could go to a circus. Here, Homer still can't have fun and even punches a clown who attempts to trick him. Bart suggests that they could see the hypnotist. The hypnotist Sven Golly makes Homer believe that he is 10 years old again before evading Chief Wiggum when it is revealed that the hypnotist is a criminal. At the hospital, Dr. Hibbert explains that the only way to bring Homer back is to contact Sven Golly again.
This forces Bart to share his room with Homer, and he is surprised when the new Homer says that when he will grow up, he will not have a job or a family. Bart makes Homer his new best friend and accomplice, to Milhouse's dismay. On the other side, Marge begins to miss her husband, despite their children having fun with him: Lisa holds a concert with him and Bart evades bullies due to Homer's protection. Chief Wiggum finally manages to capture Sven Golly and plans to bring him back, but he and Marge discover that Homer and Bart left the house and ran off to Itchy & Scratchy Land.
Homer is finally caught and torn between his love for Marge and his new bond with Bart. He chooses the former and says goodbye to his best friend, advising him to be 10 years old forever. Sven Golly then brings Homer back to his old self, but before Marge can explain what happened, Homer assumes that the reason of his presence at Itchy & Scratchy Land was because he was drunk and asks for forgiveness, which Marge gives. At the end of this episode, Homer confides to Bart that he had a special friend as a kid but can't remember who it is. He also decides not to strangle him again and rather wants to begin a new step with him. Then, it is revealed that Marge asked Sven Golly to make Homer more affectionate. Later, in a specially made cell, it is revealed that Sven Golly managed to hypnotize Wiggum into thinking he is the actual prisoner and is left locked in the cell before being visited by Loki.