While driving Bart and Lisa to school, Homer discovers how "uncool" his children think he is. To prove them wrong, he buys tickets to the Hullabalooza music festival for himself, Bart, and Lisa.

As the rock bands perform, Homer tries unsuccsessfully to blend in. Forcibly escorted to the fringe of the crowd, a projectile prop pig flies into his gut at point-blank range. Homer's rugged abdominal constitution helps him withstand the force of the pig. When this talent is recognized, he joins the Hullabalooza freak show, during which a cannonball is shot at his stomach.

When Homer's stomach starts making strange noises, a veteranarian warns him not to perform anymore. However, Homer is determined to pursue his new career in rock and roll. Hullabalooza's next stop is Springfield, where Homer's family attends the show. Homer strides out on stage, but when the cannon is fired, he steps aside, explaining to his family that they mean more to him than having a "cool" job.