University student Nagisa becomes the tutor of high school student Kokusai. Despite their contrasting personalities—Nagisa being serious and responsible while Kokusai is carefree and charming—they develop a close bond. As they spend more time together, Nagisa finds himself drawn to Kokusai in ways he hadn't expected. Their relationship faces challenges as they navigate personal feelings, societal expectations, and their own uncertainties about love.

A spin-off film directed by Kazuhiro Teranishi, depicting the events leading up to "TOKYO24." The story is set in Tokyo in 2025. Haruhiko Goto, a detective in the First Investigative Division, lost his mother to a lonely death in the past. Together with his junior detective, Tsuyoshi Tojo, he is assigned to the case of a woman's lonely death, but...