During the Springfield Swap Meet, Bart and Lisa notice an album cover showing Homer. They ask Homer when he recorded an album. Homer answers that he recorded an album in 1985. He mentions that every afternoon at Moe's, Chief Wiggum, Principal Skinner, Apu, and he would get together and sing.
Homer says that his group was a barbershop quartet, which was popular everywhere, even at church. The group initially started in Springfield, but quickly found national fame after their new agent, Nigel, approached them and said everyone in the group could sing except Chief Wiggum, who was too "Village People." The group held auditions for a replacement, with Grampa (who did a swing version of Old MacDonald had a Farm), Groundskeeper Willie (who sang Petula Clark's Downtown), Jasper (who sang Theme To a Summer Place with made up lyrics), and Chief Wiggum (in disguise, performing If I Can Walk With the Animals) all making unsuccessful attempts. When the barbershop trio returned to Moe's, they heard Barney singing in a beautiful Irish voice, and were amazed. After Barney is chosen as the new member, people still liked Chief Wiggum. After hearing him sing, however, the audience warmed up to Barney.
The group considered various names to call themselves, deciding their name should be witty initially, but should become less funny each time you heard it. They finally agreed on calling themselves "The Be Sharps."
Back in modern times, leaving the swap meet, Homer says he sold a spare tire, but unfortunately, a tire on the car blows out and Marge has to take a long walk to a gas station. Homer tells the rest of the story: he tried writing a new song with little luck, until Marge got a "Baby on Board" sign. This inspired Homer to write his Baby on Board song inspired by the fad. The group sang it in studio and put it on their first album, With the Be Sharps, a parody of The Beatles album "With the Beatles". The song became a number one hit. The group arrived in New York in 1986 to perform at the centennial of the Statue of Liberty (parodying the Beatles´ presentation in 1964 on the Ed Sullivan Show). The Be Sharps also won a Grammy for "Outstanding Soul, Spoken Word, or Barbershop Album of the Year" from David Crosby, and Homer got to meet George Harrison, but was distracted by the brownie in his hand. Meanwhile, Wiggum's singing career (now dead) was being mocked by numerous talk show hosts, much to his anger.
The name of their second album was Bigger than Jesus, (the album cover parodied The Beatles' Abbey Road and the title parodied John Lennon saying the Beatles were bigger than Jesus). Unfortunately, while the Be Sharps were becoming popular, Marge had problems raising the children, and the Be Sharps had problems of their own. They had creative disputes, brought on by Barney's new girlfriend (a parody of Yoko Ono). The two recorded a "Revolution 9"-like piece, with Barney's girlfriend reciting "Number 8" over and over atop tape loops of Barney's belches. The group lost its popularity and split up, with Principal Skinner returning to Springfield Elementary School, Apu returning to the Kwik-E-Mart to continue gouging customers, Barney returning to Moe's with his girlfriend, and Homer returning to his job at the Springfield Nuclear Power Plant after a chicken named Queenie took his place. Despite numerous unanswered questions, like where the money Homer made went and why he never hung up his gold records, Homer simply sends the kids to bed and tells them he'll answer their questions another day.
After Homer takes another look at the album, the group reunites to perform a rooftop concert at Moe's. The singing causes the crowd to stop what they are doing (much to The Human Fly's annoyance), and also had a "newspaper saleskid" scamming a walker into buying a newspaper under the pretense that the Be Sharps had an article (despite their not being any actual news about their comeback or even the Be Sharps being mentioned at all). During the concert, George Harrison pulls up in his limousine, sees them and says, "It's been done," referring to the impromptu concert on the Apple offices rooftop performed by The Beatles during their Get Back recording sessions. Before the episode finishes, it is implied that Chief Wiggum, although impressed at the sight, nonetheless plans to have the group arrested (or at least tear gassed). Upon finishing their song, Homer then thanks everyone for attending, and then proceeds to jokingly hope that they've passed the audition, although Barney didn't get the joke.