28-year-old Shoko Otsuka reminisces about a boy she liked in high school. His name was Mizuno. However, when she mentions him to her close friends from that era, no one seems to remember him. While thinking about this boy she was infatuated with back then, she begins to develop feelings for a new coworker. Finally, their romance blossoms, just as Shoko learns the truth behind why her love in high school never came to be.