Aoi Yamada is a high school girl living in extreme poverty after losing her parents. She receives financial support from the wealthy Kisaragi family, whose daughter Yukari is her classmate and close friend. Aoi has long harbored a quiet crush on Souta Kazama, her childhood friend and a medical student who also works as the girls' tutor. However, knowing that Yukari is in love with Souta, Aoi locks away her own feelings out of gratitude and loyalty.

When Yukari’s father arranges a political marriage between Yukari and Hagane Takatori, a young and successful company CEO, Aoi sees an opportunity to repay the Kisaragi family’s kindness. She volunteers to become the Kisaragi’s adopted daughter and takes Yukari’s place as Hagane’s bride, despite never having been in love before.

The marriage begins as a formal arrangement, but Hagane is unexpectedly forceful and affectionate, pursuing Aoi with a mix of intensity and sweetness. Aoi is caught off guard by his attention and begins to develop confusing new emotions for him. Complicating matters further, Souta confesses his own long-hidden love for Aoi and asks her to call off the marriage. Torn between her lingering feelings for Souta, her sense of obligation to Yukari, and the growing pull she feels toward Hagane, Aoi is drawn into a turbulent love square.

As the story progresses, Aoi must navigate her shifting relationships: Yukari’s hidden jealousy, Souta’s earnest pleas, and Hagane’s persistent and passionate pursuit. The narrative explores Aoi’s gradual understanding of love and desire, the sacrifices made for family and friendship, and the question of whether a marriage born from obligation can transform into genuine romance. The manga follows Aoi through the highs and lows of her arranged marriage, culminating in a resolution that forces her to choose the person she truly loves.