The family is at Paradise Pier, the Ferris wheel of which Marge has been looking forward all her life to riding, only to find out that it is being dismantled with some of its equipment being sold. Homer purchases a dumbbell while Marge gets a tandem bicycle. When Marge wants to take the bike for a ride, she finds Homer, Bart and Maggie unwilling to join her.
She tries it on her own and repeatedly falls. Realizing that his mother might actually be lonely, Bart offers to go for a ride with her. They ride into an unincorporated part of the county and come upon a small village that features a tea house. Later, the tea house closes forever due to poor sanitation, causing Bart to invite his mother to his treehouse for tea.
Marge redecorates the treehouse and the pair goes off to get a new tea service; Bart gets a Krusty Teapot. Outside the store, the bullies Jimbo, Dolph and Kearney accuse Bart of being a mama's boy, which causes Bart to rebel on Marge. Marge goes into a depression and eventually sells the bike to Chief Wiggum, Eddie and Lou.
Feeling bad, Bart offers to team with her in a karaoke contest. While seeing Principal Skinner and his mother perform, Marge has visions of a terrible future for Bart, and she stops the show to let Bart know that he can find his own way of life and that he should not worry about her because it is her job to worry about him. To make things better, she gives him a fire extinguisher to spray in front of the audience, including the bullies that teased him.
Meanwhile, at Moe's, Homer shows off the strength in one of his arms he has gained from working with the dumbbell, and Moe has an idea on how to capitalize on it. Moe takes Homer to the arm-wrestling championships, where Homer readily wins the grand prize—a refund on his $50 admission fee—but finds that he really misses his wife.