The episode begins with the preparations of the students of Katagiri High School for their annual sports day. The class representative, despite his gloomy appearance, promises to play fair on behalf of all the students. The main characters, including Miyamura, participate in various competitions, with Miyamura showing a newly discovered determination to win.

The first major event is a hurdles race, where Hori and Ayasaki compete against each other. Ayasaki, motivated by Miyamura's cheers, takes an early lead but stumbles at a hurdle. Hori, who was initially behind, speeds up toward the end of the race and achieves a good result, much to the surprise of her classmates.

Next, the students participate in a scavenger hunt. The goal is to find the object or person listed in an envelope and bring it to the finish line. As fate would have it, both Hori and Miyamura draw slips that require them to find the student council president, leading to a comedic battle over who gets to bring him to the finish line. The event ends in a tie, as both teams cross the finish line at the same time.

The final event is a cavalry battle, a game where student teams try to eliminate the opposing team's "rider." Miyamura, acting as the rider for his team, manages to outwit the opposing rider, Sengoku, securing victory for his team.

The episode ends with the students cleaning up after the event. Hori, now wearing a cheerleader outfit for a group photo, is teased by Miyamura about her sunburn. Despite the teasing, Miyamura compliments Hori, calling her "super cute," which flusters her. The episode reaches its climax as Miyamura reflects on how much he enjoyed his first—and possibly last—sports day.