Lisa and her girlfriends realize Bart has targeted them for a spitball attack. As spitballs rain down upon them, Lisa runs for the house, only to find the back door locked. Bart fires a final spitball at Lisa’s face, hitting her in the forehead. Lisa holds up the spitball, which has blood on it. Bart realizes it came from a loose tooth in his mouth. Eventually the tooth comes out, and Bart places it under his pillow. The next morning Bart discovers the tooth fairy has left him a note, saying a donation has been made in his name to the United Way. Marge tells Bart the tooth fairy left him a grown-up gift. Later Bart gathers up some of his favorite toys and sets them adrift on a raft. He then sets the raft on fire.

Bart tells Lisa he’s having a midlife crisis. Lisa says that when she feels depressed, she writes in her diary. She encourages Bart to write something of his own. Bart takes a marker and writes “Adults Suck, Then You Are One” on his red shirt. The slogan is a big hit with kids at school. Later he creates more t-shirts, and his fan base grows. Bart begins selling the t-shirts, which are a huge hit. Lisa thinks Bart might have a chance at landing a distributor at the Springfield Novelty Expo. Bart attends the expo but doesn’t land a distributor. While walking away from the convention center, Bart gets hit by a car. The driver, Goose Gladwell, a Willy-Wonka-ish man in a colorful top-hat and suit, offers to sell Bart’s t-shirts in his stores. Later Goose shows up at the Simpson house and gives Bart an envelope stuffed with cash. Mr. Burns catches Homer asleep at his workstation. Burns suspends Homer without pay, but Homer say his son is making so much money he doesn’t need to work anymore. Soon after, Homer asks Bart for a handout every time he needs some money.

As Homer lies on the couch, watching television, he sees an English documentary about lions, hosted by Declan Desmond. Declan points out that when an aggressive young lion challenges an alpha-male ruling a pride, the alpha-male has two choices: spend the rest of his days among broken-down lions, or find solace by caring for vulnerable young cubs. Homer chooses the later. He begins paying more attention to Lisa, and when she runs into problems with her science-fair project, showing the history of nuclear physics, Homer promises to help. He breaks into the power plant’s plutonium storage area and makes off with a glowing rod. Soon after, Homer completes work on his own nuclear reactor. Meanwhile Goose Gladwell announces he sold the rights to Bart’s t-shirt line to Disney. Unfortunately Bart gets nothing from the deal. Homer approaches Goose and threatens to detonate the reactor if he doesn’t give Bart what he deserves from the sale of the t-shirt line. Goose opens a wall safe and hands Homer a stack of cash. Later Homer and Bart bring the reactor to the town dump.