In Episode 11 of "Suki na Ko ga Megane wo Wasureta" titled "On the Day of the Cultural Festival: The Girl I Like and I...", the episode begins in Class 3-B, where Mie-san and Komura-kun exchange their morning greetings. Mie-san drops something small, prompting Komura-kun to ask if she has piercings. This thought occupies his mind throughout the day.

Later, Mie-san clarifies that it was a pearl for an octopus project they will present at the upcoming cultural festival. Komura-kun is relieved but still can't stop thinking about Mie-san having piercings. They discuss their feelings about piercings and both admit that they find the idea scary.

The episode then shifts to the preparations for the cultural festival. Mie-san decides to stay longer to help, despite the strict curfew at 6 PM. Komura-kun worries about her decision but continues working alongside her. Mie-san misses three calls from her mother and hastily leaves the school, forgetting her regular shoes and wearing her sneakers instead.

Komura-kun finds Mie-san's shoes and decides to return them. He goes to her house, where he meets her mother and explains the mix-up while handing over the shoes. The next day, both are relieved that the shoe incident didn’t cause any major issues.

The episode ends with Mie-san and Komura-kun at the cultural festival. Mie-san reads Komura-kun’s diary entry and finds it carefully written and amusing. In an empty classroom, Mie-san closely examines Komura-kun’s face, which she finds calming. However, she decides to control this habit and compares Komura-kun to a "father" figure in her life. This makes Komura-kun reflect on the nature of their relationship.

The episode concludes with a preview of the next episode, hinting at a cooking training day where Komura-kun and Mie-san are not in the same group.