Ōkiku Nattara Onna no Ko begins with a quiet wish from a young boy named Shuuichi, who tells his childhood friend Ryouko that he wants to become a girl when he grows up. Raised in a household of women after his father left, Shuuichi is drawn to feminine clothing and expression, and rather than dismissing his feelings, his mother and grandmother support him. The story follows Shuuichi as he starts living as a girl at home and eventually in public, navigating elementary and middle school under the watchful care of Ryouko, who tries to protect him from bullying and confusion.

The central conflict emerges from the gap between Shuuichi’s inner identity and the expectations of the outside world. While he is happiest wearing dresses, growing out his hair, and being treated as a girl, Ryouko struggles with her own feelings—she has always liked Shuuichi as he originally was, and she fears that his transformation will take him further away from her. Their relationship becomes the emotional core of the series, as Ryouko grapples with jealousy, protectiveness, and the question of whether she can love Shuuichi for who he truly wants to be.

The setting shifts between Shuuichi’s home, where his identity is accepted without question, and school, where rumors and curiosity create tension. Notable narrative arcs include Shuuichi’s first experience wearing a school uniform designed for girls, a summer festival where he dresses in a yukata and passes effortlessly among strangers, and a painful episode where a classmate discovers his secret and threatens to expose him. Another significant arc involves Ryouko’s romantic confession, which forces Shuuichi to confront whether he wants to be loved as a boy or a girl. A later story follows a side character, a boy named Hiroshi who befriends Shuuichi and develops feelings for him without knowing his assigned sex at birth, leading to a complicated triangle of secrets and self-discovery. By the final chapters, Shuuichi accepts that he does not need to choose a single label, and the manga closes on a bittersweet but hopeful note as he and Ryouko reaffirm their bond, no longer defined by gender but by the years they have shared.