Free! -Iwatobi Swim Club-

Even though it has been a year since the Iwatobi High School Swim Club has been created, new members have yet to join the club. Now that Haruka Nanase and Makoto Tachibana are senior students, along with their younger friends Nagisa Hazuki and Rei Ryuugazaki, they have to find a way to attract new members. If not, the club will be forced to close the following year due to a lack of membership. Meanwhile, with impending graduation, it is also time for the seniors to decide their plans for the future. Unlike their friend Rin Matsuoka, the new captain of Samezuka Academy Swim Club who is determined to fulfill his dream of being a professional swimmer, Haruka and Makoto are unsure about what career path they want to take. Further problems arise when an old friend of Rin's, Sousuke Yamazaki, comes to the city to study at Samezuka Academy; the recently scouted swimmer's arrival causes tension in the relationship among him, Rin, and Haruka.

Haruka Nanase, now attending college in Tokyo, has an unexpected encounter with Shiina Asahi, an old friend and teammate from his middle school years. This encounter leads old and painful memories to resurface, while new challenges await on the road to competing on an international level.

Taking place between the events of Free!: Eternal Summer and Free!: Dive to the Future , Free!: Take Your Marks plays out the graduated seniors' last summer through four different stories before they set sail for the future. Unmei no Choice! (Destined Choice!) follows Haruka Nanase and Makoto Tachibana searching for a new apartment for Haruka as he settles into Tokyo. Hitou no Cooling Down! (Cooling Down at the Secret Hot Spring!) sees Aiichiro Nitori choose a graduation gift for Rin Matsuoka and Sousuke Yamazaki, while Momotaro Mikoshiba wins tickets to the Anago Hot Springs. Hoping for a trip together, Aiichiro and Momotaro invite Rin and Sousuke. Kessoku no Batafurai! (United Butterfly!) shows Rei Ryugazaki, Nagisa Hazuki, and Gou Matsuoka creating a recruitment video to attract new club members for the next school year. Tabidachi no Etanaru Buru! (Departing Eternal Blue!) looks into the Iwatobi and Samezuka swim teams' plans for Rin's surprise going-away party, as he will be departing for Australia soon.

Kaname Okiura, a student of Prefectoral Umineko Shougyou High ("Umishou" for short), joined the school's swimming club in order to learn how to swim, but the club is filled with weirdos, let alone who can teach him swimming. Then, a sunny, happy-go-lucky girl named Amuro Ninagawa who transferred from Okinawa joined the club. Her extraordinary underwater speed and unorthodox swimming style (plus her personal habit of nude swimming—a powerful magnet to teenage boys) surprised every club member, especially Okiura, because she reminds him of a mermaid-like creature he saw only once in his early childhood.