Haruka Nanase and Makoto Tachibana have entered middle school, confronting the changes that accompany growing up. While Makoto blends with his peers and stays optimistic about swimming, Haruka finds it hard to make friends or join the school"s swim club because his past difficulties with water still haunt him. He distances himself from his energetic classmates and the swimming club, struggling to choose an alternative group. The rest of the class, including Makoto, also hesitate over which clubs to pursue. After a heated debate pushes them into the swimming club anyway, the boys work to sharpen their abilities, align their techniques, and resolve their mixed emotions about swimming and one another.
With determination and skill soaring, Haruka, Makoto, and their classmates discover themselves and enhance their talents during those early days. They learn that perseverance can transform challenges into together triumphs.