初中一年级的夏天，在大赛混合泳接力上没能得出结果的遥决定以接力赛队员的身份进行集训。那天晚上，醒来的遥向游泳池走去，看见了郁弥一个人仰望星空。

现在生活在澳大利亚的凛，每天和来自世界各地的游泳运动员一起努力训练。然而，一个日本人出现在他的队伍训练的地方，向他的队友们发起挑战，并逐一击败他们。当这个新来的人说出自己的身份时，连凛都感到惊讶......

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.

The Iwatobi High School Swim Club is participating in a joint training camp with the Samezuka Academy and Soufuukan High School teams. Sousuke is also participating as an alumnus. In the midst of the excitement, Rei and Nagisa notice that something is odd about Romio's swimming. Then Shizuru tells them the story of what happened to Romio in middle school...

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.

With the college championships approaching, all the swimmers are training hard on their own in addition to their official club practices. Haruka is also undergoing some extra training, with coaching from the mysterious man they've been seeing around campus. Makoto is concerned about the arrangement, but Haruka assures him that he asked for the help himself

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.

Haruka's next race is the All-Japan Invitational, which determines who will represent Japan at the global level. To prepare for this important tournament, Haruka is invited to a special training camp.

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.

Makoto meets up with the members of the Iwatobi Swim Club who are in Tokyo for the nationals. Meanwhile, Haru continues his training.

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.