Norwegian winter, 1915. On the island Bastøy, outside Oslo, a group of young boys aged 11 to 18, are held in an institution for delinquent youth, notorious for its sadistic regime. One day a new boy, Erling, arrives, determined to escape from the island. After a tragic incident, he ends up leading the boys in a violent uprising. When the boys manage to take over the island, 150 soldiers are sent in to restore order.