老迈但却充满活力的工厂主中岛喜一(三船敏郎饰),在听说美国进行氢弹实验之后,就购买了一块土地修建地下室,以防备核辐射。后来,他又听说苏联也在进行氢弹实验,放射性尘埃能从北面吹到日本,于是就放弃了修建地下室的计划,打算全家移居巴西。周围的人都觉得他杞人忧天,大惊小怪。家人极力反对他的计划,并以精神失常为由,请求法院禁止他处理家族财产。中岛喜一为了断绝家人的后路,一把大火烧毁了自己的工厂,却没料到这一举动导致了工人的失业。中岛喜一最终发疯,进了精神病院。Kiichi Nakajima, an elderly foundry owner, is so frightened and obsessed with the idea of nuclear extermination that his family decides to have him ruled incompetent. Nakajima's fervent wish is for his family to join him in escaping from Japan to the relative safety of South America. Harada, a civil volunteer in the case, sympathizes with Nakajima's conviction, but the old man's irrational behaviour prevents the court from taking his fears seriously.