Mayu has a brief flashback to a time when she was little and a nice boy saved her from bullies. However, her "prince" later turned out to be a girl, or more specifically, Kazuki Kosuda, the sister of the boy she has a crush on.
Back at school, the students are preparing for the upcoming school festival. Yamada is still trying to find a way to seduce Takashi Kosuda, when he mentions that he's going to be developing some photos in the darkroom and invites Yamada to come along. Yamada thinks she'll finally get her chance at sex, and starts sliding off her shirt, but at the same time gets a little skittish when Kosuda starts poking her breasts by accident while looking for the light switch.
In the next part of the episode, Yamada reflects on the fact that she "levelled up" by getting Kosuda to touch her breasts, and thinks the school's culture festival will be the perfect place to (again) have sex with him. However, things don't quite go as planned when Kosuda spends most of the festival with his photography and Yamada nearly flashes her friend Takeshita instead in the haunted house.
Later, Yamada ends up in a school-wide beauty contest, where she finds her reign challenged by a mysterious foreign exchange student from American named Kyouka Kanejou. However, she manages to win in the end and keep her popularity. When Yamada offers to dance with some students near a bonfire later that night, Kosuda finally decides to go down and meet with her. However, the line is incredibly long and by the time he gets to dance with Yamada the festival is officially over, but they decide to dance anyway.