From the introduction: For over a thousand years humanity has been controlled by the tyrant know as Lordgenome, this man wiped out all of civilization and now rules over the earth from a massive fortress city known as Teppelin. The few humans that remain live underground in small villages, unable to return to the surface because of the threat of the beastmen and their powerful Gunmen mechs. However, in just a few short years a young boy named Simon will discover a mysterious mech hidden deep beneath his village and set off a chain of events that will lead to a rebellion against earth's cruel tyrant. You arrive three years before the end of the battle of Teppelin and you'll have to survive in this world for a total ten years.