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.