Bart and Lisa browse at the flea market and discover a record album with Homer's picture on the cover. Homer recounts how in the summer of 1985, he, Chief Wiggum, Principal Skinner, and Apu formed a barbershop quartet...

At the behest of their manager, Nigel, the group replaces Wiggum with Barney, who has a beautiful tenor voice, and calls themselves "The Be Sharps." Inspired by Marge, Homer writes a song, "Baby on Board," which becomes a hit. The group's album receives a Grammy award for their first album and they become the focus of a mass merchandising campaign. Homer even meets George Harrison.

The band's meteoric success is short lived. Marge finds that with Homer constantly on the road, she cannot manage raising the kids by herself. There are diasagreements over lyrics and personal friction amongst the band members. Barney dates a Japanese conceptual artist named Kako, whom the others reguard with contempt. After five and a half weeks, the band finally splits up...

Homer finishes the story and, feeling nostalgic, gathers with his former band members for a reunion on the rooftop of Moe's Tavern.