Takeshi Nanjo, a junior lieutenant in the navy whose father, the head of the Nanjo-gumi yakuza family, was killed, is forced to leave the army and become the head of the Nanjo-gumi in the second generation. He brutally chivalrously avenges the death of his father by a vicious yakuza linked to extremists within the army through the courage and swordsmanship of naval training!