Lisa's eighth birthday is approaching, and to make sure that Bart doesn't forget, she reminds him of the forthcoming event. Meanwhile, Homer is horrified to discover that Bart has tossed his lucky red hat into the washer along with his white dresshirts, turning the shirts pink. When Mr. Burns spots Homer on a video surveillance monitor, he detains him for being a radical, pink-clad troublemaker. Dr. Monroe gives Homer a sanity test to take home, but afraid that he will answer the questions incorrectly, Homer has Bart fill it out. After Monroe scores the test, Homer is placed in the New Bedlam Rest Home for the Emotionally Interesting.

At the institution, Homer meets a big white man who talks like, dances like, and thinks he is Michael Jackson. Not knowing who Michael Jackson is, Homer believes him. Michael telephones Bart to tell him that Homer is in a mental institution and needs the love of his family more than ever. When Marge arrives at the rest home to get Homer released, Homer invites Michael to come home with him.

Lisa's birthday arrives and Bart forgets to buy her a gift. Lisa disowns him as her brother. To bring the siblings back together, Michael helps Bart write a birthday song for Lisa. Lisa forgives Bart and thanks him for giving her the best present ever. Feeling good about himself, Michael admits that his name is really Leon Kompowsky. Talking in his normal deep voice, Leon leaves to help more of his fellow men.