Shuji Nagasawa is a low-ranking otaku who spends his school days keeping his head down, pretending to be asleep to avoid interaction. Miran Hanazuki, a flashy gyaru who sits at the top of the school caste, keeps approaching him with teasing, flirtatious behavior that leaves him bewildered. Before he can make sense of her motives, his parents drop a bombshell: he has a fiancée, and it turns out to be Miran. The two are bound by a family agreement, forcing the introverted boy and the outgoing gyaru into a sudden, inescapable engagement.

The story follows Shuji and Miran as they navigate this absurd arrangement. At first, they view each other through stereotypes—he sees her as an unapproachable party girl, while she sees him as a boring recluse. But the forced proximity of shared meals, secret meetings after school, and a weekend alone together when both parents are away begins to break down those walls. Shuji discovers that Miran is far more caring and domestically skilled than her appearance suggests, while Miran finds comfort in Shuji’s honest, nonjudgmental attention. A third party, Kaede, who has quietly watched Shuji from afar, grows anxious as the pair grows closer and decides to act, introducing a mild romantic rival dynamic.

The narrative arcs revolve around the couple learning to trust each other beyond the engagement contract, overcoming external pressures from peers and friends who don’t understand their relationship, and gradually shifting from reluctant obligation to genuine affection. The story balances comedic misunderstandings with sincere moments of vulnerability, as both characters shed their social masks and grow through each other’s influence.