In the harsh streets of Tokyo in the tumultuous year of 2020, crime runs rampant, particularly crimes against women ranking second only to murders. Raised as a boy by her parents to shield her from the dangers of the city, Tsukasa dreams of following her parents' footsteps as a police officer battling the notorious yakuza. Tragedy strikes when her parents perish in the line of duty, leaving Tsukasa and her three brothers to navigate the treacherous urban landscape alone. To repay the family's debts, Tsukasa is compelled to take on the role of a bodyguard for Ryuji, her classmate and the formidable leader of Tokyo's most influential yakuza syndicate.