Early in the second world war, a young soldier sent as part of an invasion force to the mainland fell in love with a local and deserted, fleeing into the jungle. This man raised his child and grandchild to believe (as he did) that the second world war was still going on, and that the absolute worst thing that could happen would be a capture by the imperial japanese government. He gave them as much military and guerilla training as he could, and they became strong and disciplined. In the present day, the last surviving member of the line is discovered by an american filmmaker looking for POWs lost in vietnam, and his existence and story is announced to the world. After that, he is subject to a series of assassination attempts by Yakuza hired by a secret society of Diet members who are dedicated to the return of the ambition and culture of the Japanese Empire -- essentially in order to destroy a source of anti-Imperial PR. However, because of his heavy training, the man survives, and decides to hunt down and kill each member of this secret society -- including the prime minister!