After the match, Haruka and the others are once again reprimanded for trespassing on Samezuka Academy grounds. Makoto and Nagisa run into Gou and they all agree that Rin's attitude had dramatically changed in the past few years, simultaneously learning that Gou had been the one who sent him to the Iwatobi Swimming Club while Nagisa suggests that they form a school swimming club.
After getting Haruka on board, Makoto and Nagisa propose the idea to their home room teacher, Miho Amakata who agrees after they give her a little prompt. Finally, the club is accepted by the faculty on the condition that they find one more member, and restore the school's swimming pool themselves. Nagisa begins the task of finding a fourth club member, which proves much more demanding than they had initially thought.
While continuing the restoration, Gou, who was still confused about Rin's behavior, asks Makoto about their race and learns that Haruka threw the match. This allowed Rin to win since he was merely content with being in the water, something which angered Rin. Believing that they can revert Rin to his old self, Gou volunteers to join the club as their manager. Later, Makoto pays one final visit to the Iwatobi Swimming Club and runs into their old mentor, Coach Goro Sasabe.
Sasabe reveals that Haruka and Rin had a race when the latter made a rare return to Japan, of which Haruka easily won. Rin was exceptionally disappointed that his hard work was for nothing, creating a rift between them, subsequently causing Haruka to quit competitive swimming because he had hurt Rin's pride. Upon learning this, Makoto calls Rin to inform them of their plans while Rin decides to join the Samezuka swim team for his own grudge against Haruka. Finally, Miho and the group officially establish the Iwatobi High Swimming Club and Haruka can't help but christen the pool with the first swim much to his friends' dismay.