Nanako Kusanagi is the fifteen-year-old daughter of the owner of the shop where Hisashi Uehara works part-time. As the boss's daughter, she develops a strong romantic interest in Uehara and actively pursues him. She initially displays spoiled tendencies, frequently teasing Nao Yoshikawa, whom she views as a rival for Uehara's affections. This behavior fuels tension in the dynamic between Uehara and Nao during their high school years.

Throughout the story, Nanako experiences personal development. Her persistent infatuation with Uehara gradually shifts towards deeper self-realization. By the manga's final chapter, she acknowledges her feelings stemmed from admiration rather than genuine love. This understanding marks her evolution beyond her earlier bratty demeanor. Her narrative centers on this unrequited pursuit and subsequent emotional growth within the main series.