Kayama Ichinoshin (Raizo Ichikawa) has been traveling for ten years in search of revenge for his father. One day, Ichinoshin reunites with his younger brother Shinjiro (Yukio Hashi), who has completely changed. Shinjiro abandoned the quiet samurai life and began to lead a Yakuza lifestyle. The older brother is angry at the younger one for his depravity, and the younger one laughs at him for being tied to old-fashioned traditions. As a result, they quarrel. Ichinoshin hears that the person he has to take revenge on has become a Yakuza, and in order to get a hint, he takes care of the Otsu family, to which Shinjiro owes, but later discovers that the boss of Otsu Kanemon is the one he is looking for.

元服早々、父の仇討ちという使命を背負わされた兄・市之進と、武家を嫌ってやくざの世界に飛び込んだ天衣無縫の弟・新次郎。生き別れになっていた二人が、因縁の運命のもと再会する。弟の腐り果てた姿に激怒する市之進と、兄の悲壮感溢れる忠実さを笑う新次郎。しかし皮肉にも市之進はやくざ修行をするハメになる。