Springfield Elementary holds a casino night as a fundraiser, the brainchild of student body president Martin Prince (elected such in "Lisa's Substitute"). Homer wins big, but when Martin points out that his winnings can only be redeemed for cafeteria scrip and not real money, the angry casino patrons riot. After the chaos has cleared, Principal Skinner tells Martin he must resign as president. An election for a new president is announced, and Lisa signs up. However, initially popular Nelson Muntz is favored to win. During a debate in the school auditorium, she sings a song (a parody of "Don't Cry for Me Argentina") about how she will fight for student rights, winning them over.
Lisa easily wins the election. Worried by her determination and popularity, the faculty discusses how to control her. Following Mrs. Krabappel's suggestion that a woman's weakness is vanity, the school faculty tells Lisa that as president, she deserves a more glamorous look. Another song is sung (a spoof of "Rainbow High") as the teachers give Lisa a makeover into a fashionable Eva Perón lookalike. She is initially resistant, but gives in since she reasons she will still be able to fight for the kids. The students love the new Lisa more than ever, but the faculty use her as a scapegoat for dropping music, gym, and art from the curriculum to save on the budget. Facing an outraged student body, Lisa realizes that she has been used by the teaching staff and had been seduced by glamor and power. After resigning as president, Lisa goes back to her old red dress and spiky hair, and leads the students in a strike.
The students leave school in protest and Michael Moore (voicing himself) shows up to take their side, stating that children who do not receive music, gym and art are more likely to become unemployed and end up in one of his movies. The police arrive at the school to handle the students with child-size batons, but Lisa soon convinces the police to take their side too. Several other labor unions, including goat milkers, newsroom cue card holders and theme park zombies join the strike. Even Groundskeeper Willie refuses Skinner's order to turn his hose on the students. Realizing there is no other way out of the crippling strike other than disposing of Lisa, Skinner has her transferred to a school for the "Academically Gifted and Troublesome". She waves goodbye to her classmates and the rest of Springfield - including Moe, who is holding a picture of her - singing another parody song ("Don't Cry for Me Argentina").
Just as Lisa arrives at her new school, Homer pulls up and refuses to allow her to attend or give up on her fight for a better Springfield Elementary, complaining that he will not drive 45 minutes each day to take her to school. He suggests she take up an activity like ice skating instead, but when she eagerly asks to do that, he refuses once again, complaining that he does not want get up early each morning.
At the end of the episode, subtitles state that Springfield Elementary was eventually able to restore music, art and gym by cancelling flu shots and selling loose cigarettes. The subtitle then states that the producers of the show, "based on the advice of their lawyers, swear they have never heard of a musical based on the life of Eva Perón".