Koizumi Chiaki is a volleyball player who wishes to learn how to swim. Every day, she would watch her school swim club after her practice without them knowing. But then one day, things take a total turn as one of the members catches her and as she's going home, she bumps into someone who also knows how to swim. Taking advantage of the situation (and her cracked phone screen) she convinces (*cough*forces*cough*) the guy to teach her how to swim. Little did she know this boy was non other than Matsuoka Rin - her friend's brother and the captain of Samezuka Academy's swim team.