The yakuza have their best days behind them and are only a shadow of themselves. The old rituals seem out of date and their tattoos make them outcasts of society. The inexperienced student Ryō stumbles into their ranks by chance, and before he knows it, he becomes entangled in dark machinations. He quickly succumbs to the fascination of omnipotence fantasies and hedonistic decadence and sinks deeper and deeper into a parallel world of prostitution, blackmail and violence. However, there is one thing that Ryō has not considered in his naivety: once yakuza, always yakuza!

Fukami is a high school janitor whose father was a gangster. He works at the school as a janitor instead of belonging to the gang so he can watch out for Yui, the daughter of his deceased father's brother Majima Yoshiki. One day, a gang feud erupts and Yoshiki is killed. Yui becomes the next target.