When Marge starts economising, Homer thinks he's being left out of the family's important financial decisions, so splashes out on an expensive camper van and sets up camp on the driveway.

After the family successfully protest against a stamp museum being built next to their house, a cemetery is built near the Simpson house instead, making the normally unflappable Lisa realize that someone as smart as her can be afraid of something.

The family is on a nature walk through “Carl’s Dad Caverns,” when Homer tries to get a piece from a stalactite. This results in the family falling through the cave floor and winds up with Homer getting stuck in the ceiling of one of the lower chambers of the cave. Marge, Bart and Maggie go off to find help, while Lisa stays behind and tells her father a story to pass the time. Her story involves running from a bighorn sheep and into Mr. Burn’s mansion. The pair evades the tenacious sheep by finding refuge in the mansion’s attic, where Mr. Burns tells her the story of how he came to work at Moe’s Tavern by losing a scavenger hunt with a rich Texan. While there he learned (and tells to Lisa) the tale of the Moe’s treasure. The stories within stories culminate in the fate of the treasure being determined in the cave.

Working through their checklists of things to do before summer ends, Lisa gets the family to go a museum. At the Springfield Museum of Natural History there is an exhibit Lisa is excited to see on Women’s History turns into an exhibit on the history of weapons, which excites Homer and Bart. When Flanders sees the exhibit of evolution and another that mocks creationism, he raises an alarm. Reverend Lovejoy gets Skinner to have creationism taught in school. Lisa is the only one who holds onto the scientific theory. She brings the topic up at the town meeting and the town votes to teach only one theory, creationism. Lisa decides to hold her own class on evolution, until she is arrested. The ACLU gives her a lawyer who is up against a slick Southern lawyer, but ultimately it’s a family member that is a key to her defense.

Lisa pretends to be Native American for multicultural day at school. Meanwhile, Bart finds love with an older woman.

In a parody of "24," the school's Counter Truancy Unit tries to stop three sixth-graders planning to disrupt the school bake sale with a stink bomb.

Homer and Marge celebrate Valentine's Day by going on the Tunnel of Love ride at a carnival, but they end up stranded when Bart pulls a prank involving gelatin. To pass the time, Homer tells the love story of Bonnie and Clyde, Marge tells her version of "Lady and the Tramp," and Bart tells the love story of Sid Vicious and Nancy Spungen.

Bart lands himself in trouble when he steals a mobile phone from Denis Leary and subsequently uses it to land the actor a comical film role. The troublemaker then leads his family to the ancient ruins of Machu Picchu after Marge confiscates the device and decides to use its GPS technology to track her son.

Marge and Lisa visit the nail salon where they engage in a spirited debate as to whether a woman can be smart, powerful and beautiful all at the same time and spin four tales of famous women featuring famous Springfield faces: Selma as Queen Elizabeth I, Lisa as Snow White, Marge as Lady Macbeth and Maggie as Howard Roark, the idealistic architect protagonist from Ayn Rand’s The Fountainhead.

When Miss Hoover asks her students to research their family history, Lisa is horrified to discover that most of her ancestors were bad people – a motley crew of horse thieves and deadbeats. But while rummaging through the attic, Lisa happens upon a diary kept by her ancestor, Eliza Simpson. As Eliza’s story unfolds, Lisa learns that her family was part of the Underground Railroad, a group that helped slaves escape to freedom. Eliza recounts liberating a slave named Virgil, but when Lisa presents her findings at school, some of her classmates refute it, leaving Lisa determined to exonerate her family’s name.