为了弘扬传统的武士道精神，培养真正的日本热血男儿，一所全日制的私塾——男塾应运而生。进入这里的男子不仅文武兼备，更要拥有坚强的意志和不屈不挠的精神。一年一度新生大会准时举行，按照惯例，所有的新生要和高年级的学长进行对决。剑桃太郎（坂口拓 饰）、富坚源次（照英 饰）和虎丸（山田亲太朗 饰）在激烈的搏斗中脱颖而出。
男塾的修行难以想象般的艰苦，而教头又有如凶神恶煞一般。此外，男塾的宿敌关东豪学连也不断发出挑战，为了维护男塾尊严，热血男儿勇敢地在“惊罗大三凶杀”中和对手展开决斗……

After four years overseas, Shozo returns to Japan to avenge his yakuza boss who was assassinated by his own treacherous top man, Kurawaki. The resulting battle leaves both men severely injured, and Shozo awakens in a mysterious medical facility to find his arm replaced with an M61 Vulcan cannon and his leg replaced with a rocket launcher. Meanwhile, Kurawaki has been fitted with mechanical augmentations of his own. Get ready for the second round.