Nina Yamada is the only female student in her class at a formerly all-boys high school. She is intensely serious and studious, focusing entirely on earning a strong college recommendation despite being called boring or overly earnest by her classmates. One day, her homeroom teacher gives her an ultimatum: if she can convince the truant Mihane Murata to return to school, she will receive extra credit toward her recommendation. Reluctantly, she agrees.

Yamada tracks Murata to a local game center and finds him surrounded by a group of girls, clearly the carefree womanizer his reputation suggests. Murata used to be the star of the archery club but stopped attending after breaking his arm, and he now avoids school altogether. Their personalities clash immediately—Yamada’s rigid sense of duty against Murata’s easygoing, evasive demeanor—yet she persists in her mission.

Over time, Yamada’s straightforward honesty begins to pierce Murata’s guarded exterior. She not only gets him to return to school but also helps him reconnect with his classmates, slowly drawing him out of his self-imposed isolation. As they spend more time together—through school events, visits to each other’s homes, and summer break—Yamada starts to recognize her feelings for Murata as romantic, while he gradually sheds his playboy persona and develops genuine feelings of his own. Their budding relationship is complicated by the presence of classmate Kato, who also has his own emotions to sort out.

The story follows their uneven, often comedic journey toward mutual understanding and love, all while Yamada learns to balance her ambition with friendship and romance. A recurring device is Yamada’s class diary, which she uses to record daily events and her personal reflections. The series spans their entire first year of high school, culminating in the couple officially dating and navigating the challenges of a new relationship.