Haruka Nanase and Makoto Tachibana navigate the challenges of middle school as they confront changes and personal struggles. While Makoto thrives socially and remains passionate about swimming, Haruka grapples with social isolation and past swimming traumas, making it hard for him to connect with others or commit to the swim club. Despite initial reluctance, a heated discussion leads them to reluctantly join the swimming club, where they embark on a journey to refine their skills, synchronize their swimming techniques, and reconcile their conflicting emotions about swimming and each other. As they unravel their inner conflicts and nurture their talents, Haruka, Makoto, and their peers embark on a transformative path of self-discovery and skill enhancement during their formative school days.