Set between Free!: Eternal Summer and Free!: Dive to the Future, Free!: Take Your Marks chronicles the final summer of graduating seniors through four distinct narratives before they embark on their futures.
Unmei no Choice! (Destined Choice!) follows Haruka Nanase and Makoto Tachibana as they search for a new apartment in Tokyo while Haruka settles into city life.
Hitou no Cooling Down! (Cooling Down at the Secret Hot Spring!) follows Aiichiro Nitori selecting a graduation present for Rin Matsuoka and Sousuke Yamazaki, while Momotaro Mikoshiba secures tickets to the Anago Hot Springs. Desiring a shared outing, Aiichiro and Momotaro extend invitations to Rin and Sousuke.
Kessoku no Batafurai! (United Butterfly!) depicts Rei Ryugazaki, Nagisa Hazuki, and Gou Matsuoka producing a recruitment video to draw fresh members for the upcoming school year.
Tabidachi no Etanaru Buru! (Departing Eternal Blue!) explores how the Iwatobi and Samezuka swim teams arrange a surprise farewell celebration for Rin, who is soon leaving for Australia.
