Marcie [Arianna McDonald] helps Peppermint Patty [Lexi Perri] practice for the upcoming school golf tournament, acting as her caddie, as five younger kids spectate. Their session features a memorable moment when a ball is retrieved from a bunker by carrying the sand:
> carrying the sand
At school, Peppermint Patty admires the school's championship cup and prematurely celebrates, while Marcie quietly points out that the caddies don’t get any mention in the accolades. Franklin then reminds the students to vote in the upcoming student council election, as his term as class president is nearly done. As other students announce their candidacies, Peppermint Patty remarks that Marcie would make a good student council president due to her helpful nature, though Marcie finds the idea daunting because the job is so busy, public-facing, and fast-paced.
As the day goes on, Marcie confronts a series of problems around the school. After mulling them over in her room, she resolves to solve things herself, but when the issues recur the next day her shyness and fear of public speaking block her from acting. She seeks out Lucy's advice at her psychiatric booth on how to be more assertive. Lucy’s guidance is not particularly helpful, and Marcie ends up rushing off to Peppermint Patty's qualifying golf game.
With Marcie's help, Peppermint Patty wins and advances to the championship. Franklin congratulates Peppermint Patty and highlights Marcie as her caddie; when asked to make a public statement about the game, Marcie is overwhelmed by anxiety, deferring to Peppermint Patty before running away. She then encounters Charlie Brown [Etienne Kellici], and the two discuss Marcie's difficulty in asserting herself or taking charge. She resolves to approach problems in her own way: to implement solutions ahead of time so she can prevent issues from arising in public.
As the results of the student council election are tallied, Marcie is elected class president through write-in votes thanks to her improvements to the school, though she dreads the public role and retreats to her room to avoid the job.
During the championship, Peppermint Patty enlists Charlie Brown as her caddie in Marcie's absence, but he does a terrible job. Seeing that Peppermint Patty is headed for a loss, Carlin [Antonina Battrick] rushes to Marcie's house to fetch her. Marcie hesitates, knowing that appearing to speak in public is daunting, but Carlin helps her realize that she can still contribute in meaningful ways without being in the spotlight. She heads to the game and, with her quiet but steady support, helps Peppermint Patty turn the game in her favor. At the last stroke, Peppermint Patty wins by carrying the sand once again.
After the game, when asked to give her first speech as class president, Marcie asks for time to prepare what to say. In a careful, thoughtful address, she resigns as class president, acknowledging that she is better suited to working behind the scenes. With the second-most votes, Pig-Pen [Lucien Duncan-Reid] is inaugurated as class president, and Marcie continues to help from the sidelines, proving that quiet, steady support can be a powerful form of leadership.