Katsuki is the only daughter of the head of the Orai-gumi, a gang that upholds traditional codes of honour. Concealing her yakuza background, she had been leading an ordinary life with her husband, Yoshio—a man from the legitimate world—and their daughter. Meanwhile, Hayakawa, who had long had his sights set on the Orai-gumi’s territory and had been reaping exorbitant profits from his casino, sets out to make Katsuki his own. To begin with, he frames the head of accounting at the company run by Yoshio in a set-up at the casino. Around the same time, Naito, the second-in-command of the Oki-gumi, is attacked by Hayakawa’s daughter, Aoi, and her associates.