Jinwoo (Jin-young) and his friends, who are each experiencing the peak of their puberty, have their own unique interests and causes of trouble. The one common interest among them is Seon-ah (Da-hyun), the model student who embodies both grace and beauty. To them, Seon-ah looks like an unattainable dream, even though she's in the same class. Despite their contrasting personalities and academic performances, Jin-woo and Seon-ah develop a close bond by showing interest in each other's different sides. Their relationship navigates through the lovey-dovey and bittersweet phases of high school and into the heart of their poignant youth.