Free!: Timeless Medley - The Promise (2017) Plot Summary Explained

During his years in junior high school, Haruka Nanase, voiced by Nobunaga Shimazaki, decided to join the swim team. However, his time there was cut short when he had a significant falling out with his rival from elementary school, Rin Matsuoka, voiced by Mamoru Miyano, who had recently returned from studying in Australia. This conflict had a ripple effect on the team, causing Ikuya Kirishima, voiced by Koki Uchiyama, to develop a deep resentment toward Haruka. Eventually, the swim team disbanded entirely as Asahi Shiina, voiced by Toshiyuki Toyonaga, moved away and Ikuya headed abroad for his studies.

As they transitioned into high school, Haruka began preparing for various tournaments alongside a new group of teammates, including Makoto Tachibana, voiced by Tatsuhisa Suzuki, Nagisa Hazuki, voiced by Tsubasa Yonaga, and Rei Ryugazaki, voiced by Daisuke Hirakawa. During this time, Rin also prepared for competitions, having reconciled with the others. Despite being in his final year of high school and even being scouted by a university during the prefectural meets, Haruka remained uncertain and had not yet formulated any plans for his life after graduation. In contrast, Makoto found a new sense of purpose and inspiration to become a swim coach after he spent time helping Hayato, the younger brother of Kisumi Shigino, learn how to swim.

The pressure reached a breaking point during the regional tournaments. Overwhelmed by the expectations of performing in front of university scouts, Haruka suffered a mental block and stopped swimming right in the middle of his individual event. When Rin confronted him about his lack of a dream or direction in life, Haruka reacted with an uncharacteristic burst of anger, which deeply concerned his circle of friends. Later, Makoto tried to reason with him, but the conversation devolved into a heated argument. During this clash, Makoto revealed his own ambition to attend a university in Tokyo to pursue his personal dreams. Feeling more lost than ever, Haruka was eventually prompted by Makoto to travel back to Australia with Rin. This trip served as a turning point, inspiring Haruka to pursue swimming at the college level. Upon returning to Japan, he made amends with his teammates and, fueled by renewed hope and the strength of his bonds, helped his team secure a 6th place overall finish at the nationals.

In a brief post-credits scene during the nationals, Sosuke Yamazaki, voiced by Yoshimasa Hosoya, finds himself lost, only to stumble upon the individual medleys. There, he witnesses Ikuya from Shionezaki High School overtaking every other competitor. Following the tournament, Ikuya discusses his physical condition with his older brother, Natsuya Kirishima.

The narrative further explores the relationship between Rin and Sosuke Yamazaki, who is Rin's childhood best friend. After transferring into Rin's class at Samezuka Academy, the two are reunited. While they had promised as children to continue their swimming careers together, Sosuke had been hiding a dark secret: he suffered from a serious shoulder injury caused by overuse. Despite the pain, Sosuke continued to push himself as they prepared for upcoming tournaments. While Rin remained intensely focused on the sport, Sosuke struggled to find a meaningful reason to keep swimming, which placed a significant strain on their friendship.

At the regional tournament, the truth finally came out, and Rin learned about Sosuke's injury. However, Sosuke, now deeply valuing the bonds he had formed with his teammates, remained determined to compete in the team medley one last time. The team fought hard and placed second in the race, successfully qualifying for the nationals. Following this achievement, Sosuke decided to stop pushing his body and seek proper medical treatment for his shoulder. Although he had to drop out of the national competition, he dedicated his time to helping Aiichiro Nitori, voiced by Kouki Miyata, and Momotaro Mikoshiba, voiced by Kenichi Suzumura, prepare for their events.

In a final post-credits sequence, Sosuke warns Rin about Ikuya, noting that Ikuya's freestyle technique is strikingly similar to Haruka's in terms of both speed and form. Meanwhile, Ikuya skips the nationals' awards ceremony to call Natsuya. As the story winds down, Gou becomes determined to recruit new members for the following school year, while Aiichiro, Momotaro, Nagisa, and Rei reaffirm their rivalry and arrange a joint practice session. As Asahi says his farewells to his team at Kazami High School, he receives a text from Kisumi. Finally, the journey continues as Haruka and Makoto arrive in Tokyo.