There's trouble at the beach. The four swim club members are forced to revisit their motivation to swim. After Rei asks Makoto about his odd behavior during the training camp, Makoto tells them about his past.

Coach Sasabe begins training the Iwatobi Swim Club for the upcoming tournament. Meanwhile, Rei is unhappy about the fact that he's the only one who doesn't know about what happened with Rin in the past. After Rin expresses his frustration, Haruka decides to tell him about what happened when they were in grade school.

The Iwatobi Swim Club must win to advance to nationals. As the tournament draws near, the members get nervous. Meanwhile, Rin grows increasingly irritated. As it comes time for the medley relay, each member must find their own answer as they step up to the start line

Haruka and his friends have grown after last summer’s tournament. Amidst the hustle and bustle of training for their individual events, their daily lives continue as usual. However, a new season now approaches!

In anticipation of the upcoming prefectural tournament, the members of the Samezuka Swim Club enthusiastically show off their individual abilities. At the Iwatobi Swim Club, an equally enthusiastic Gou proposes a lunchbox inspection to ensure the boys are getting the right nutrition to support their training. However...

Haruka and the boys have trained hard to prepare for this showdown against Samezuka. After Day 1 of the tournament, Gou and Amakata-sensei treat the boys to a fabulous, carb-rich feast and allow them to take a breather. Meanwhile, Rin is faced with a tough decision as captain of the Samezuka Swim Club. Who will he choose to swim the relay with him?

The Iwatobi Swim Club continues their training. However, signs of confusion seem to keep surfacing in the silent Haruka’s swimming. Makoto and the others are worried about him, but try to continue acting cheerfully as though nothing was wrong. But one day, Sousuke appears, asking to speak to Haruka…

Haruka and his relay teammates decide to hold a training camp in the summer of their second year of middle school. During the night, Haruka heads out to the pool and finds Ikuya looking up at the stars.

Haru, Makoto, and Asahi visit Shimogami University in hopes of talking to Ikuya, but even after looking all over campus, they can't find him. Hiyori, however, notices them and makes it his mission to keep them from seeing Ikuya.

Hiyori still remembers the first time he saw Ikuya smile. Both boys grew stronger through rigorous training while they studied abroad in America... but seeing Haruka threw Ikuya off his stride. Now Hiyori wishes Ikuya would just forget about Haruka for good.

After the breakup of his middle school swim team, Ikuya decided to get stronger on his own and not rely on anyone. But Haruka, breaking out of his freestyle comfort zone to swim in the individual medley, tells Ikuya that he's not alone.

Makoto has been unable to get in touch with Haruka following the friendly race at his training camp, making him worry that Haruka is dwelling on what happened. Then Nao approaches Makoto to tell him about a rumor he heard.

Nagisa, Rei, and the rest of the Iwatobi Swim Club have come to cheer on their former teammates at the All-Japan Invitational. Makoto tells them the story of how ever since Haruka swam for the first time, he'd been swimming only freestyle.