Haruka Nanase and Rin Matsuoka are both gifted swimmers who are friends, but fierce rivals in the pool; their lives and the lives of their friends are chronicled as they compete alongside and against one another.

The members of the Iwatobi Swim Club ponder over the cause of Nagisa's odd behavior at the end of practice that day; though they time their chance well to ask Nagisa what's happened, Nagisa stubbornly refuses to explain why he's upset.

On the eve of prefecturals, Makoto resolves himself to broach a certain subject with Haruka; as the tournament begins, the Iwatobi Swim Club is extremely enthusiastic about its prospects.

Haruka and the boys train hard to prepare for the showdown against Samezuka; after Day 1 of the tournament, Gou and Amakata-sensei treat the boys to a carb-rich feast and allow them to take a breather.

While Haruka and the boys redouble their training in the wake of prefecturals, Makoto notices Gou looking troubled and asks her what's wrong; she tells him that Coach Sasabe has been busy with his Swim Club lately.