Rin Matsuoka/Story

Free!
While Haruka Nanase, Makoto Tachibana and Nagisa Hazuki are walking down the corridors of the old Iwatobi Swimming Club building, they run into a young man. When they find out that it is actually Rin in front of them, completely changed, they are shocked. Rin immediately challenges Haruka to a race until they discover that the old pool is empty.

Haruka, Makoto and Nagisa learn from Rin's sister, Gou Matsuoka, that Rin has returned from Australia and that he's attending Samezuka Academy, a school known as a swimming powerhouse. Afterwards, Makoto and Nagisa convince a reluctant Haru to visit Samezuka by tempting him to a swim duel in the school's pool. Upon arriving, they wait until the school's swimming team is done with practice, then break into the academy's swimming pool. They are discovered by Rin, who aggressively orders them out. Haru then steps out of the pool and challenges Rin to a freestyle match.

Later on, Goro Sasabe (first seen as a pizza deliveryperson), meets Makoto unexpectedly and reveals that Haru and Rin had a race during junior high school, when the latter makes a rare return to Japan, and that Haru easily wins. Rin is exceptionally disappointed about the loss, telling Haru that he's done with competitive swimming. Believing his efforts at improvement have been for naught, this event creates a rift between the two boys. It also causes Haru to quit competitive swimming, as well, because he believes himself to be the sole cause of Rin's decision. Upon hearing this, Makoto calls Rin to inform them of the plans to re-form the Iwatobi High School Swim Club. In return, Rin joins the Samezuka Swimming Club as a means to settle his grudge against Haruka.

Hoping to bring her brother and his old friends closer, Gou arranges for a joint practice between the Iwatobi and Samezuka swim teams. Upon learning about this, Rin questions his sister's true intentions, but shows no sign of protest. With a new member, Rei Ryugazaki, on their team, the Iwatobi team shows up, ready to swim with the first year students of Samezuka. Rin leaves the room, dismissive as he says that their team is nothing but a waste of his time but, shortly thereafter, reappears in the bleachers, curious as Gou notes, about how they will all perform.

Following the joint practice, Rin often spends his free time practicing and training, taking along his roommate, kohai and fellow swimmer, Aiichiro Nitori. After another night of vigorous training, Aiichiro mentions offhandedly how inspirational watching Haruka's team had been, much to Rin's displeasure. As Rin prepares to leave for a jog, he says their team is out of shape and needs to improve immensely before they end up in any tournaments together. He believes that Haru must be in top form for any personal win to feel gratifying.

At Dolphin-S, a sporting goods store to which the Iwatobi team goes to purchase Rei new swimwear, Haru and Rin run into each other and have a short discussion about their differing forms with Rin wanting to race when they are both in peak condition, or else he won't be able to move forward in his Olympic quest. They decide to settle the score at the upcoming tournament.

The Iwatobi team decides to conduct a summer training session at a island in order to swim in the ocean. Upon arrival, they coincidentally discover the Samezuka Swim Club, along with Rin, training at a special swimming facility there. As the Iwatobi team prepares for dinner, Gou heads to a nearby convenience store and runs into Rin, who shows brief but genuine concern for Makoto after Gou explains their training. He returns to usual stoic self, offering to walk Gou to the hotel in which she and Miho Amakata are staying.

Unaware of the trouble the Iwatobi boys are in, Rin wakes up in the middle of the night to the sound of a storm raging outside his window. Early the next morning, he runs along the beach but pauses when he spots the two tents the Iwatobi team had set up for the night. Shortly after seeing them swimming back to shore, however, Rin runs off to continue his practice.

It's the day before prefecturals and Rin wakes up from a harrowing nightmare involving his father. In it, Rin is visiting Haru's house. When no one opens the door, he invites himself in and finds a goldfish bowl with a single goldfish swimming about inside. The sound of footsteps distracts him and, startled, he turns to find Haru standing in the doorway. Haru tells him that he only swims freestyle, then walks away. Rin promptly chases him and winds up at the edge of a large swimming pool. He's about to engage in a race but before he can reach his starting platform, he spots his father as a child, holding a large trophy won in a medley relay with his team. His father runs and Rin pursues, chasing him from the pool to the narrow streets of Iwatobi. Ultimately, he loses sight of him after passing through a bright tunnel and ending up in a procession of old priests in white clothing. Rin runs beyond the procession but pauses to look back, catching sight of a younger version of himself holding Gou's equally young hand. The child Rin mutters incoherently just before Rin startles himself awake -- shaken, gasping, and sweating with fright.

At practice that day, Aiichiro confronts Rin and asks him why he decided to join the "100 meter freestyle crawl" rather than the butterfly, Rin's best stroke. Rin dismisses the conversation though Aiichiro suspects Haru may be involved in Rin's decision. That evening Aiichiro brings up the conversation with Rin again as he helps him train in their dorm room. Aiichiro confesses that he's upset with Rin for choosing the freestyle crawl when he clearly has the potential for something much greater. He admits to wanting to be in the 100 meter crawl instead of the 400 meter, to which Rin expresses a bit of regret. Rin boosts Aiichiro's confidence when he tells him he has endurance and will last in the 400 meter crawl to which he is assigned. He tells Aiichiro he's going to visit his father's grave before the meet, which Aiichiro misunderstands as a suicide threat. Rin reassures him, then relates his father's past, along with his reasons for wanting to become an Olympic swimmer. Rin adds that if he cannot beat Haru in a true race, he won't be able to accomplish that goal.

On the day of prefecturals, Rin visits his father's grave, asking that his spirit watch out for him as he wins his big race. At the competition venue, Haruka and Rin meet briefly in the hallway. Rin tries to rile Haru up by telling him he may not even make it to the finals to race him. In the race to make finals, Haru loses to Rin and as Rin exits the water, confident and cocky after his first place win, he tells Haru he will no longer swim with him ever again, a statement which hurts Haru, leaving him silent and alone in the pool.

After his loss, Haru heads to the locker room, his long absence concerning his teammates. They rush into the building to search for him. In doing so they bump into Rin who boasts his win and tells them there is nothing more important to him that winning in a swimming race. Makoto interjects, telling Rin that what truly matters in a race is swimming together with one's teammates. Rin abruptly cuts him off then strides away, unwilling to deal with confrontation or sentimental speeches with the Iwatobi team. Regardless, as Rin spends his time waiting in the Samezuka bus, he considers Makoto's words about Haru wanting to swim with him more than anything.

In the end, no one in the Iwatobi team makes the cut for finals, but Gou surprises them when she confesses that she signed them up for the medley relay portion of the preliminaries to be held the following day. That day, as Rin sits by himself in the hallway, Aiichiro approaches, excited when he says the Iwatobi team will be swimming in the relay. Something seems to spark inside of Rin and he runs out to watch. As each swimmer breaks the surface of the water, he comments on the unique swimming style he remembers all too well from when they used to swim together. Watching Rei swim, however, irritates Rin because Rei has since replaced him as their butterfly swimmer. As Haru dives in, Rin watches with anticipation. Haru eventually wins the race for the team and as they all celebrate together Rin can only watch on in silence, his thoughts drifting to when they all won and swam together as children.

Summertime rolls around and the streets of the Iwatobi Town light up with squid-shaped lanterns and row upon row of brightly colored stalls during the annual Squid Festival. The Iwatobi boys venture out to enjoy themselves at the event, but both Nagisa and Rei end up distracted when they spot Rin and Aiichiro walking together amidst the crowd. Wanting to prevent Haru and Rin from meeting, in case they fight, Nagisa has Rei spy on Rin while keeping in touch with him through text messages. Eventually, both Makoto and Haru discover Rei and Nagisa's plans just as Rei manages to follow Rin to a building on the outskirts of the festival. The building is Iwatobi Elementary School and just beyond the chained link fence, Rin spots the large cherry blossom tree standing proudly before a small swimming pool. Once again his thoughts drift to memories of when he was a child -- laughing, swimming, and having fun with his teammates. Their voices resound in his mind and he remembers how it used to feel to cheer each other on in the heat of a race. Shortly after, Rin breaks into a run back towards the Iwatobi train station where he confronts Samezuka team captain, Seijuro Mikoshiba, to inform him that he wishes to participate in the medley relay.

After the festival, Rei expresses his confusion about Rin and the Iwatobi boys' past. He wants to know why Rin would choose to swim in the medley relay and why he is so hellbent on defeating Haru in every race. Haru explains their history, mentioning the story of Rin's father and his race against Rin during junior high school. Rei fails to understand why their friendship would be so broken, so the following day, he skips out on swimming practice for the finals in order to confront Rin with his questions.

Rin and Rei end up in a heated argument involving Rei blaming Rin for Haru's past rejection of competitive swimming and explaining to him how important swimming with his team is for himself. Shocked, Rin can hardly fight back and in the end they part ways, Rin more disturbed than ever. Captain Mikoshiba and the rest of the Samezuka team observe in Rin's performance, during relay practices, how distant and disconnected he appears. However, no one speaks with Rin nor expresses their concern and Samezuka ends up leaving on schedule for finals.

In the city where finals are being held, the Iwatobi team settles down for sleep. Rei receives a strange message from Rin and they meet up atop a hill in the middle of the night. Here, Rin speaks his mind and the reasons for his behavior become apparent. He admits Haru's win during junior high school wasn't the reason he quit competitive swimming. Instead, he blames himself for not pushing himself harder when he had the chance. In Australia, Rin struggled and hardly ever placed high in the ranks. Frustrated, he blamed his history with relays and assumed he had grown too attached to them back home. He never contacted his teammates whenever he would return to Japan because he was too embarrassed to admit his losses, growing ever more distant and isolated from that past life. Rin ends the conversation by telling Rei not to embarrass or let down his team at the finals tomorrow.

Rin arrives back at the hotel where the Samezuka team is staying where Aiichiro informs him that Captain Mikoshiba would like to have a brief word. As it turns out, Mikoshiba, concerned about Rin's condition, has rearranged the schedule to place Rin back into 100 meter crawl race instead of the medley relay. Rin is taken aback, worried he truly will never be able to swim with his teammates ever again.

Rin sits despondently in the back of the Samezuka bus on the day of finals with Aiichiro trying his best to encourage him. If anything, the younger boy only irritates Rin even more and Rin storms out to prepare for his race. At the opening assembly, Gou watches from the bleachers as the swimming teams gather. She spots her brother amidst the other Samezuka swimmers, though he appears listless, tired, and in no condition to be swimming at all. However, Rin carries on, though he experiences a late start, resulting in a disappointing loss in last place. As Rin struggles to push himself out of the pool, Haru abruptly stands, hoping to find Rin and help him however he can. The rest of the Iwatobi team follows, sacrificing precious time before their own race begins. They follow the sound of a loud voice down the hallway and, sure enough, find Rin screaming at Aiichiro, proclaiming how terrible he was and how he refuses to keep swimming anymore. Those familiar words rattle the onlookers, though none more than Haru who now fears he will truly never swim with Rin again. Once Rin and Aiichiro disappear from sight, Rei admits his conversation with Rin and explains to them Rin's true feelings. Rei realizes how badly his teammates want to swim with their old friend, so he sacrifices his in the relay provided they can find Rin and persuade him to swim with them one more time.

Check-ins for the medley relay begin just as the boys rush out in search of Rin. Haru eventually finds him standing beneath a large tree, its branches bare but stretched out wide towards the sky. Rin is upset when he speaks to Haru, and even orders him to laugh at him just as the rest of the world must be doing. Haru tries to reason with Rin by explaining how he, himself, now understands what he swims for: his team. Now angry, Rin charges at Haru, grabbing him by the collar of his jacket as he yells at him to keep quiet. Again Haruka refuses to respond, angering Rin further and the two wrestle one another to the ground as Haru narrowly blocks Rin's incoming punch. They struggle for only moments when, something catches Rin's eye and he pauses. His grip loosens on Haru when he sees the words etched into the dirt at the base of the tree. The words read, "For the Team," a phrase that Rin, as a child, painted on a brick for a school project to represent what matters most to him. Earlier that day, Haru had visited the tree, which reminded him of the sakura tree at their elementary school, and scratched those words into the ground with a twig.

When Haru asks if Rin came to the tree because of its resemblance, Rin's tears fall onto his cheek. Between sobs, Rin admits that all he ever wanted to do was swim with his friends again. Haru gives him a knowing smile just before Makoto, Rei, and Nagisa appear. Together, they convince their friend to join them as a relay member.

With seconds to spare, Makoto, Nagisa, and Haru show up to check-in for their race and, from the bleachers, Gou and the rest of their cheering squad remain unaware of their plan. First to swim is Makoto with a backstroke, followed by Nagisa with his breaststroke and just as their supporters note how they are far in the lead, Rin appears on the starting platform, shocking everyone in the Samezuka bleachers. Regardless of the inevitable consequences, Rin prepares for Nagisa to touch the wall before he dives in, swimming quickly and fluidly, as if with new purpose. As he swims, Rin sees a light underwater and enthusiastically swims towards it, pushing in the last few meters of his crawl so Haru can complete the race. As he looks up, Rin watches in awe at the sight of Haruka diving in above him. Finally, after cheering with his team, Rin watches as Haru touches the wall of the pool first, winning the race for the team. Unable to contain his joy and relief, Rin rushes to embrace his friend as he thanks him for showing him the best sight ever. As the four team members celebrate and hug together, Rei watches on, commenting on how beautiful all of them truly are.

As expected, the team suffers great consequences for allowing a member of another team to swim in their race. Thus, the Iwatobi team is disqualified and ejected from the tournament. They all accept their loss without regret and can only smile knowing that, in truth, winning is not what matters most. Elsewhere, Rin bows deeply before his captain and requests he be kicked off the swimming team for his reckless and disappointing behavior. He also apologizes to Aiichiro for snapping at him when Captain Mikoshiba cheerfully orders him to swim as he did for Iwatobi, but for Samezuka. Rin stays on the team, much to his surprise.

Following the events at finals, Rin regularly swims and hangs out with his friends on the Iwatobi team. He can be seen after hours at their school, standing before Haru, Makoto, Nagisa and Rei as he reenacts the time he had to introduce himself at their elementary school as the new transfer student. Gou and Aiichiro interrupt the boys to drag them to joint practice and as they all run together towards the pool, Haru asks Rin if he still intends to follow his father's dream. Rin responds with confidence, telling Haru he now only wishes to follow a dream of his own.

Free!–the Final Stroke– the second volume
Rin participates in a four-swimmer relay at the Fukuoka Tournament with Haruka Nanase, Ikuya Kirishima and Sosuke Yamazaki. They take first place.