Despite the fact that it has been a year since Iwatobi High School Swim Club was founded, no new members have joined yet. With Haruka Nanase and Makoto Tachibana being senior students along with their friends Nagisa Hazuki and Rei Ryuugazaki, they are now faced with the challenge of attracting new members to keep the club running. If they fail to do so, the club will have to close down due to insufficient membership.
In addition, as graduation is approaching, Haruka and Makoto must decide on their future plans. Unlike Rin Matsuoka, who has a clear goal of becoming a professional swimmer after being named captain of Samezuka Academy Swim Club, they are uncertain about what career paths to pursue.
Furthermore, the arrival of an old friend of Rins, Sousuke Yamazaki, who is studying at Samezuka Academy, creates tension among him, Rin, and Haruka due to a recently scouted swimmer.
The series won the 2014 Animage's Anime Grand Prix Award.