The Children's World(2013)

The girls and boys of this world are in a constant war with each other: the boys have occupied an abandoned city while the girls live in a hidden forest. But when Albert, one of the boys, wounds a girl during a battle he decides to take care of her and follow her into her forest. Suddenly a new world opens up for him, and the revealing secrets Albert is about to discover changes him, and the rest of the world with him.