After viewing a commercial for the latest game system, Bart tosses his “old” station into the fireplace. When his attempts at getting Marge and Homer to purchase him a replacement go nowhere, Bart gets a job as a doorknob menu hanger at a Thai restaurant. Lisa is appalled by the waste of paper used to make the menus. Later, the Simpsons drive to Krustyburger for a meal. On the roof of the restaurant are four protestors, clad in cow suits, who blame Krusty’s corporation for the destruction of rainforests used for cattle grazing land. A nervous Krusty denies the charge, then grabs a beanbag-firing rifle from a cop and opens fire. The cows are pelted with the bags. Moments later, Wiggum approves the use of gas, which knocks a cute teenage boy with short blond dreadlock off the roof. Lisa is immediately smitten with the cute protestor, who is taken away in a police car.

Lisa learns through a television news report that the object of her affection is Jesse Grass, head of the eco-radical group Dirt First. Later, Lisa visits Jesse in jail. She is thrilled by his dedication to his cause, and even more so when she learns about an upcoming meeting. Later, at a warehouse, Lisa listens with rapt attention as Jesse addresses a group of fellow activists. First on the agenda is a major crisis: Springfield auctioned off the logging rights to the city’s oldest redwood tree, and now, a Rich Texan intends to cut it down. Lisa tells the others they must fight to save the redwood. Later, Lisa asks Homer and Marge for permission to do so, but her request is denied. That night, Lisa slips away and gathers the courage to climb the mighty tree. She reaches a level bough and sets up camp. The following day, when the Rich Texan and his men show up to cut down the redwood, Jesse points to the little girl sitting in the tree. The ploy works: The Texan’s plans must be put on hold. But as the days pass, Lisa longs to be with her family. In the middle of the night, Lisa abandons her post, intending to return in an hour. But when she comes home, she falls fast asleep and doesn’t awaken until the next morning. Horrified, Lisa leaps on her bike and pedals back to the tree. But when she reaches her destination, all she discovers is a jagged stump.

While watching a news report, Lisa learns that the tree was not cut down, but was hit by lightning. At first, Lisa’s guilt subsides. But then she realizes that the lightning was attracted to a metal bucket she left on the tree branch. Reporter Kent Brockman relays word that the fate of Lisa Simpson (who had last been seen in the tree) is unknown. Lisa tells her family that the world must know she isn’t dead. That is, until the Rich Texan announces his intention to turn the entire forest into the Lisa Simpson Wilderness Preserve. Jesse even cuts off one of his dreads and makes a memorial to his comrade. Lisa decides she must remain in hiding, for if the world finds out she’s alive, the preserve will be lost and Jesse will discover it was her fault that the tree was hit by lightning. Later, townspeople gather at the forest for a memorial in Lisa’s honor. The Rich Texan seizes the opportunity to unveil not a nature preserve, but an amusement park in Lisa’s honor. Outraged, Lisa steps forward. The Dirt Firsters then cut lose a tree, or “Lisa log,” sending it sliding down a hillside and smashing into a Hemp City store. Later, Lisa again visits Jesse in jail, where Marge sees Jesse kissing her daughter on the forehead. Marge grabs Lisa by the arm and pulls her away. Meanwhile, the “Lisa log” continues its path of destruction.