Naoki Satoya has been Ryuunosuke "Ryu" Oohara's best friend and closest confidant since childhood, despite the fact that most of their peers fear Ryu's family, the powerful Oohara yakuza clan. Now, just months before Ryu is scheduled to inherit his father's position, he announces that he prefers to become a train conductor and live a quiet life with Naoki. Refusing to let their legacy fade away, the Oohara clan recruits Naoki to persuade Ryu to change his mind. However, when Ryu remains resistant even to the words of his favorite person, Naoki begins to wonder if there is a deeper reason behind Ryu's refusal.