"Hanakimi" centers on Mizuki Ashiya, a Japanese-American girl who disguises herself as a boy to transfer into the all-boys high school, Osaka High School, in Japan. Her motivation stems from her admiration for Izumi Sano, a high jumper she saw compete in the United States. Mizuki believes Sano has the potential to achieve greatness in the sport and wants to support him. Upon enrolling, Mizuki becomes Sano’s roommate, navigating the challenges of maintaining her secret while forming close bonds with her classmates.

The narrative explores Mizuki’s daily life as she balances her dual identity, her growing feelings for Sano, and her interactions with the diverse cast of characters at Osaka High. Sano, initially aloof and focused on his athletic career, gradually becomes aware of Mizuki’s true identity but chooses to keep it hidden, developing a protective and affectionate relationship with her. The story delves into themes of friendship, identity, and self-discovery as Mizuki’s presence impacts those around her, including her classmates, who each have their own struggles and aspirations.

The supporting characters include Nakatsu Shuichi, a classmate who becomes Mizuki’s close friend and unwittingly develops feelings for her, unaware of her true gender. His confusion and emotional turmoil add a layer of comedic and dramatic tension to the story. Other notable characters include Hokuto Umeda, the school doctor who discovers Mizuki’s secret early on and becomes a confidant, and Minami Nanba, a flamboyant and eccentric student who provides comic relief while also contributing to the series’ exploration of gender and identity.

The plot progresses through a series of episodic arcs, blending humor, romance, and drama. Mizuki’s secret is repeatedly threatened, creating moments of suspense and emotional intensity. The series also examines the pressures and expectations placed on the students, particularly Sano, who struggles with his family’s legacy in athletics and his own passion for high jumping. As Mizuki’s relationships deepen, her presence inspires those around her to confront their insecurities and pursue their dreams.

"Hanakimi" balances lighthearted moments with poignant reflections on adolescence, identity, and the complexities of human relationships. The story culminates in a resolution that ties together the characters’ growth and the central romance, leaving a lasting impact on the school and its students.