A prequel to the 2013 Kyoto Animation series Free!, the initial novel follows sixth grader Haruka Nanase as he organizes a relay squad comprising his childhood companion Makoto Tachibana, an exuberant junior named Nagisa Hazuki, and the freshly enrolled student Rin Matsuoka. The subsequent novel unfolds during Haruka and Makoto's inaugural year in middle school, chronicling their journey in the swim team alongside two fresh faces, Ikuya Kirishima and Asahi Shiina.