Asami Onohara is a 17-year-old high school student secretly married to her physics teacher, Kyosuke Ichimaru, facing a central conflict due to her father’s prohibition on sexual contact until graduation – a restriction she actively works to overcome. Attractive and well-developed for her age, past experiences with unwanted male attention fostered her dislike for men prior to meeting Kyosuke. Her attraction began when he served as her supportive home tutor, leading to their marriage before he became her teacher.

Personality-wise, she exhibits unwavering devotion to Kyosuke, viewing love and marriage through a naive, "fairy tale" lens. She embraces wifely duties like cooking meals for him, though her attempts at seduction or romance often meet comedic obstacles, primarily interference from her father. Her compassion is evident when she adopts and cares for a stray kitten named Kuri.

External challenges include rivals pursuing Kyosuke: fellow teacher Iwasaki, who later attempts blackmail upon suspecting their relationship, and neighbor Sakura Mizunosaki, a single mother who initially pursues him but later becomes an ally. Male attention from classmates also occurs, though she remains oblivious or dismissive, focused solely on Kyosuke.

Her persistent efforts culminate in the couple deciding to breach the contract and consummate before graduation. Her stated post-graduation goals focus exclusively on domestic life as a wife and mother.