Nanase Haruka loves to be in the water - loves swimming. In elementary school, Nanase Haruka, Tachibana Makoto, Matsuoka Rin, and Hazuki Nagisa swam together as a team. Time passed, and as Haruka was living an uneventful high school life, he suddenly encounters Rin again. Rin challenges Haruka to a race and shows him how much stronger he has become. Soon enough, Makoto and Nagisa also rejoin the group, and along with a new classmate, Ryugazaki Rei, they establish the Iwatobi High School Swimming Club.