Bart is watching a program featuring a well-endowed female vampire, Booberella. Homer sees a televised advertisement for a new brand of Krusty Burger, called the "Ribwich", a sandwich where the meat consists of an unidentified animal; even the ribs are made of meat. He is sold immediately and can't wait for it to come to Springfield. The next day, the vacations are over, and the kids are back in school. Principal Skinner couldn't be happier (though Groundskeeper Willie is less than enthusiastic after his paycut). During the assembly, Skinner announces that the school is holding a spelling bee for all the students. At the end of it all, Lisa wins it and gets a "scale model of the planet Mars", which in actuality is just a kickball with the word "Mars" written on it; more importantly, she is selected to go to the state Spelling Bee finals. If she wins that, she will make it to the "Spellympics", the Olympics of Spelling.
Lisa is excited at the prospect of winning a state Spelling Bee and that learning does have its merits. Later, as Homer walks around town, he sees that the Ribwich has come to the Krusty Burger in Springfield. After sampling one, he gets addicted and eats many, drooling all over the place. Lisa, meanwhile, wins the state Spelling Bee (cheered on by her own cheering section) and qualifies for the Spellympics, to be held in Calgary. Marge suggests they celebrate by watching a movie, but Homer says he can't make it as he has "important daddy business", which turns out to be going to Krusty Burger with Lenny and Carl to eat more Ribwiches. Unfortunately, the Ribwiches are no longer in stock as it was only a limited-time sandwich. Homer is shattered, but a "Ribhead" (a fan of the Ribwich) tells him that it is being tested in other markets and shows him a tour schedule. Homer decides to follow a group of Ribheads as they track the release of the Ribwich.
At the Spellympics, hosted by George Plimpton, Lisa wins the semi-finals and secures a spot in the finals, but Homer says he still cannot attend, as he wants to eat Ribwiches in the last release in San Francisco. The other two finalists are Sun Moon, an Asian girl, and Alex, a really cute little boy with big round glasses, whom everyone likes. George Plimpton takes Lisa aside and gives her a speech about the low ratings that Spelling Bees generate, thanks to the dominance of reality shows. He tells her to take a dive and let Alex win. She is shocked and refuses to do it. George tells her that if she does it, she will be given a free scholarship into any Seven Sisters college of her choice; plus, she gets a free George Plimpton hotplate. Now, Lisa is torn between wanting to win the Spellympics and free college.
That night, she dreams of the Seven Sisters (in an ancient Greek setting), where each Seven Sister college tries to lure her to her college (Plimpton also appears to add "and a hot plate!"). She wakes up and asks Marge whether they can afford to send her to college. Marge is unsure, but promises to do whatever it takes to get Lisa into college. Despite Marge's reassurances, Lisa is still uneasy.
At San Francisco, Homer pigs out on all the Ribwiches that he can find. Suddenly, a limousine pulls up and Krusty pops out of the sun-roof and informs all the Ribheads that the Ribwich can no longer be made, as the animal from which it is made is now extinct, mentioning that it was made of a small animal with "more legs (than a cow)." He tosses the last one into the crowd. Homer catches it and fights off all the other Ribheads. A few Ribheads make offers. When one Italian Ribhead promises him "the lease-a of my car", Homer suddenly remembers Lisa and the Spellympics. He gives the Italian his Ribwich, grabs the car keys and takes off in guy's sports car, giving the Italian "buyer's remorse" after finishing the Ribwich.
Meanwhile, the Spellympics finals are underway. Lisa is still unsure about what to do. George Plimpton deliberately asks Sun Moon to spell "whether/weather" and confuses her with the sentence (he uses them both), and disqualifies her when she starts "W-E...". Next is Alex's turn. He gets the word "rigged" and spells it correctly. Finally, Lisa steps up and is asked to spell "intransigence". She is about to start, when Homer shows up and shouts encouragingly at her. Lisa, happy that Homer came, tells everyone that she was told to take a dive and proceeds to spell the word, but she spells it "I-N-T-R-A-N-S-I-G-A-N-C-E". She is disqualified and George tells her that now she gets nothing (for squealing) and leaves.
On the way back to Springfield, Lisa is crestfallen at having lost the Spellympics. Homer tries to cheer her up, but she feels that she has let down the whole town. However, on reaching home, she finds that half the town has assembled at the Simpson residence to felicitate her. Mayor Quimby tells her that even though she did not win first prize, she has done better than anyone else in Springfield (even outachieving the Springfield woman who once dated Charles Grodin!). They have even carved out her likeness in a mountain nearby. Lisa is thrilled to bits.