It's a time of warfare where relentless battles continue between human and demi-human tribes like the Ash Monkeys (Macaque) and pig people (Ogres) invading human lands. Kai, a boy from the village of Rag, spends his days immersed in battle to protect his village. Amidst the harsh battles enforced by those possessing immense power known as "guardian bearers," and as his comrades fall one by one, Kai suddenly recalls memories he shouldn't have experienced—memories of a world with advanced technology and knowledge of people's lives beyond this world. And thus, although Kai was just a villager, he soon finds himself embroiled in great trials… A magnificent fantasy tale unfolds, chronicling the struggle and growth of a single boy in a harsh world.