Opening Credits: Blackboard Joke: None Couch Gag: Cut-outs of the Simpson family in the fashion of paper dolls stand in their underwear in front the couch. From off camera, a pair of large hands reaches in and places clothes on the Simpson family paper dolls and then they sit down on the couch.
Act One: In the living room, Homer naps and Marge relaxes with a book, while Lisa frets over having to give a presentation of her Simpson family heritage during Multicultural Day at school. Lisa explains to Marge that she is having a hard time with the presentation because the Simpson family history is uneventful and boring.
That night Lisa's struggles with her presentation continue, until Bart shows Lisa a gag he has devised with a Lake Land Butter package. Using some creative cutting on the package, he shows Lisa how the Native American woman on the package can, "Show me her boobs!" Lisa doesn't laugh at Bart's joke and quickly reminds Bart that Native Americans "are a proud people with a noble heritage." As she scolds Bart, Lisa suddenly comes up with the idea to fake her family heritage for the presentation at school; she quickly concocts a new family history that includes her ancestors as members of the fictional "Hitachee" tribe.
The next day at school, Lisa, sporting the corn-on-the-cob style drapes from the kitchen and red war paint, gives a rousing presentation during Multicultural Day. An impressed Principal Skinner announces that Lisa will represent the school with her presentation at Springfield's Multicultural Center. A nervous Lisa, not wanting to let on that her entire presentation was a lie, agrees to give her presentation at the Center.
Inside the barn at the Spuckler family farm, one of Cletus's kids proudly shows off the C- he earned for his presentation during Multicultural Day at school. As Cletus and his son head into the house to tell Brandine about the presentation, Cletus tugs on the tail of one of his cows, thus setting off a Rube Goldberg type of chain-reaction. As Cletus watches the elaborate chain-reaction his jaw drops, causing the lit pipe in his mouth to fall to the ground and ignite some hay. A fire rapidly develops and the flames quickly travel through the town of Springfield. As the flames reach Springfield elementary, Principal Skinner and Groundskeeper Willie try to put the fire out, but they are shocked to discover that someone has stolen all of the school's fire extinguishers.
On a nearby road, Bart straps on a helmet and climbs into a wagon with the school's fire extinguishers mounted on it. Bart simultaneously pulls all the cords on the extinguishers and the pressure from the white foam that shoots out of the extinguishers, rockets Bart down the road in the wagon. Bart speedily races through the main street in town and single-handedly puts out the spreading fire, as his white foam exhaust puts out the flames. After the wagon finally comes to a rest, a large crowd gathers around Bart and praises his "heroic" fire fighting. As a reward for saving Springfield, Mayor Quimby offers Bart the privilege to drive and issues him a driver's license.
Act Two: A re-creation of The Simpsons opening title sequence ensues: Rather than Bart skateboarding home from school, he makes his way home driving a car.
At the Springfield Multicultural Center, Lisa once again gives her presentation about her native "Hitachee" people. Once she finishes to a round of applause, she nervously tries to exit the Center, however she is stopped by a real Native American, John Squawking Bear, who is a reporter for "The Chippewa Bugle." John Squawking Bear explains that he thought he knew about all of the Native American Tribes and that he has never heard of the "Hitachee." He asks a nervous Lisa a few questions about the "Hitachee" people and she quickly offers up some fake answers.
Back at home, Bart grabs the car keys and announces that he is going to head out, but Homer stops Bart in his tracks, and gives him a cell phone so that he can keep in touch with Bart when his newly licensed son is out cruising around. Bart's new cell phone quickly becomes a nuisance to him though; that night while he sleeps, a drunk Homer calls from Moe's and asks Bart for a ride home. Bart's patience with having to be Homer's chauffeur runs thin and in an effort to get away from Homer for a while, Bart drives to neighboring town, North Haverbrook.
As Bart cruises around downtown North Haverbrook, he spots a group of teenage girls. He pulls up to them in the car and puts on some charm. One of the girls, impressed with Bart, hops into the front seat. The girl introduces herself as Darcy and she and Bart quickly take a liking to each other. A montage ensues: Bart continues to drive to North Haverbrook to spend time with Darcy. The two enjoy walks at sunset and make-out for the first time at a drive-in movie.
As Bart and Darcy rest on the hood of the car on a cliff overlooking North Haverbrook, Darcy takes Bart by surprise and asks him to marry her. A nervous Bart gulps and tries to grasp what Darcy has said to him, but she quickly pressures him into saying yes. An overwhelmed Bart wonders to himself if he is the first guy to ever be pressured into marriage.
At the North Haverbrook courthouse, as Darcy and Bart prepare to sign a marriage license, Bart comes to his senses and explains that he can't marry Darcy. He admits that he is only ten years old and Darcy is shocked at the revelation. She replies with a shocking truth of her own and tells Bart that she is pregnant. In the snap of a finger, Bart is quickly out in the parking lot trying unsuccessfully to start the car and leave.
Act Three: Back inside the courthouse, Darcy explains to a bewildered Bart that he isn't the father, the real father is a foreign exchange student who has already gone back to his home country, and that she wanted to get married so that the baby would grow up with a father. She continues to explain that the only way her parents wouldn't kill her when they found out about her pregnancy, would be if she was married. Bart takes pity on Darcy and agrees to marry her and bear the responsibility of fatherhood. At the advice of the clerk at the courthouse, Bart and Darcy head off to Utah to get married.
Meanwhile, in Capital City at the convention center, a National Tribal Conference is being held and Lisa is one of the speakers. As Lisa stumbles through her speech in front of a large audience of Native Americans, she finally breaks down and admits the truth about the "Hitachee" heritage. The audience quickly turns against Lisa, and Homer ushers her off the stage, while a flaming arrow lands on his forehead.
A quick cut to Bart and Darcy shows them making their way through the desert with Bart behind the wheel. While, back at home, as Homer and Lisa return from the National Tribal Conference, a worried Marge shows them a note Bart has written, informing them of his plans to get married to his pregnant girlfriend. As Marge and Homer head out to track down Bart, Darcy's parents show up at the door worried about their daughter and the four of them speed off to Utah.
At a wedding chapel just across the Utah state border, Bart and Darcy prepare to exchange vows, but just before they can, their parents burst through the chapel doors and stop the wedding. As Darcy's father moves in to harm Bart for impregnating his daughter, Darcy steps in and explains that Bart isn't the father. Darcy's problem with her parents is quickly solved when after her mother reveals that she too is pregnant, her father concludes that they can lie to the neighbors and explain that the two babies are twins.
Back at home, Homer tucks Bart into bed and tells him that someday he'll make a great father. For old time's sake, Homer asks Bart if he will drive him around town as he sings "public domain songs out the window." Cut to Bart driving a drunken Homer around town as they sing Twinkle, Twinkle, Little Star.
End Credits: The normal Simpsons theme plays as the credits roll over a black background.