Ryuichi and his twin sister Kiya recently passed sixteen winters. They lived well on their parents' mountain farm, where they bred dragons. It’s just a shame that the father refuses to take the children with him to the city and does not let them leave their native valley at all until they turn eighteen! But one day the outside world, huge, amazing and deadly magical, burst into their lives. And soon the twins were destined to find out why their father was so insistent that they master the art of war to perfection...