Kasumi Takenaka shared a classroom with Aoi Yukimura since middle school, yet years passed without a single conversation between them. Kasumi’s hesitation to approach the frequently isolated Aoi—whose shy demeanor and fear of heights kept her distant—left their relationship dormant until Season 3. That year, Kasumi steps into group activities alongside Aoi and classmates, including a karaoke outing spearheaded by Mio. Joined by Hinata and Yuri, the gathering signals a turning point in their dynamic. Though Aoi battles self-consciousness about her singing, Hinata’s supportive nudges cultivate a welcoming atmosphere, paving the way for Kasumi and Aoi’s first meaningful exchange in a social setting.