The Kanto Kurogane Federation stands at the pinnacle of Japan's yakuza society. Sakaki Sai (Sho Aikawa), the young boss, secures his position with the help of his covert private force, known as the “Chain,” led by Hidari (Hideo Nakano), Yamato (Yasukaze Motomiya), and Hakase (Shiro). One day, the federation's second-generation boss is shot dead, and Sakaki is arrested as the prime suspect. In his absence, acting young boss Takewaki (Ryu Kanou) is entrusted with leading the group, eagerly bribing executives in a bid to secure the vacant third-generation boss position. Sensing something suspicious about both the assassination and Takewaki’s ambitions, Sakaki unleashes the "Chain" to uncover the truth in his stead…