日本战国时代，东海道甲斐的武田信玄（中村锦之助 饰）以《孙子兵法》中的“风林火山”为军旗，征战四方，立下赫赫威名。中年浪人山本勘助（三船敏郎 饰）用计投入武田信玄帐下，在武田攻略昔日盟友诹访的过程中，山本堪助全力配合主公的背义战略，击破诹访，虏获诹访家千金由布姬（佐久间良子 饰），山本堪助劝说美丽的由布姬做杀父仇人信玄的侧室，并决心扶立二人的子嗣为武田家之主。信玄在山本等家臣的辅佐下与村上等强敌连番激战，而为了实现自己对由布姬承诺的山本堪助也在暗中为这对儿母子进行谋划…… 本片改编自井上靖的同名历史小说。Feudal Japan, 1543 to 1562. Kansuke Yamamoto is a samurai who dreams of a country united, peaceful from sea to sea. He enters the service of Takeda, the lord of Kai domain. He convinces Takeda to kill the lord of neighboring Suwa and take his wife as a concubine. He then convinces the widow, Princess Yu, to accept this arrangement and to bear Takeda a son. He pledges them his life. He then spends years using treachery, poetic sensibility, military and political strategy to expand Takeda's realm, advance the claim of Yu's son as the heir, and prepare for an ultimate battle with the forces of Echigo. Has Kansuke overreached? Are his dreams, blinded by love, too big?
