Kaoru Hanabishi appears to be an average university student, but in actuality, he's the eldest son of Yūji Hanabishi, the head of the Hanabishi Zaibatsu, and was set to take over the zaibatsu after his father retired. His mother, Kumi Honjō, and his father never married, making life difficult for both him and his mother. Kaoru's father died when he was five years old. Since then, Yūji's grandfather, Gen'ichiro Hanabishi, took Kaoru under his wing and began educating him for the eventual succession. Yet Kaoru never felt at home in the Hanabishi family and left to live by himself after his mother died. Day by day he felt alone, thinking that he was living life with no reason pushing him on.
There was, however, someone who loved Kaoru so much that she'd do whatever was necessary to be with him.
Her name is Aoi Sakuraba. Aoi is the only daughter of the owner of the Sakuraba Kimono (Dry Goods in the manga) Store (later renamed to Sakuraba Department Store). Kaoru's family and Aoi's family had agreed for Kaoru to wed Aoi, but after Kaoru walked out, the marriage was canceled.
