The affluent and respected Shiunji clan is made up of seven siblings: Banri, Seiha, Ouka, Arata, Shion, Minami, and Kotono. As the designated heir, Arata is constantly ridiculed by his sisters for never finding a partner. Yet on Kotono"s fifteenth birthday, the family discovers a startling long‑hidden truth—each of them is adopted.
The siblings vow that their bond will stay unchanged in the face of new revelations. That pledge, however, frays quickly as each sister starts to pursue Arata with feelings that transcend mere family affection. Arata, who values his kin above all else, must now safeguard their treasured ties and keep the Shiunji household intact.
