“Sometimes even to live is an act of courage.” Year 5500 F.T. humanity almost fell. A chaotic moment that is recorded on the history.  The First invasion war won by Humanity and drove the Grays to the corner. After several years, the Grays have returned to rule the world once more.  Will Lou and his Stigma Alps be able to conquer the obstacles in his path and save the world from the Grays, or will the war bring humanity's end?