Shima (2007)

1975. The journalist Shintaro, who is looking for his father, finds himself on an island with a group of people he hardly knows. Their guide captain Yamada, leaves Shintaro and his fellow-travelers on the island where they are captured by a mad soldier. All attempts to explain things to him are useless. The crazy warrior is sure that the Second world war is till going on. After a month on the island under the command of the nutty soldier they start believing in it themselves. Soon they get the guns and set to work, strengthening their lines, getting ready for the attack of an unknown enemy.