Prologue

It's been a long while since the Great Disaster of human race happened. We counted how many years we've spent in the underground, hidden from the monsters that, once, were friends, and now, forced us into this place.

Even though some of us were born in the underground, I doubt most of us remember what the heat of the sun feels like. I know, also, that's not the whole story.... Parts are missing. The monsters wouldn't have attacked for no reason... Or would they?