Yō Saegusa, a reserved fifth-grade student and classmate of Tsubomi Tachibana, holds widespread popularity as "the class idol." His older sister mentors others, notably guiding Yae Yamabuki through puberty-related concerns. Within his social circle, he befriends Daiki Nemoto and Futoshi Kuki. A secret romance with Yae Yamabuki blossoms in chapter 5, concealed to avoid inciting jealousy among classmates. Their relationship culminates in a kiss during chapter 9—a pivotal moment witnessed by Tsubomi and Daiki that ignites romantic awakenings in the observers.