In ancient times there was vibrant on earth the mechanical civilization was highly developed .
but one day magic mech betray human and bring a severe desaster.
To facing these threats of disaster beast and magic mech . suviver build up a new sanctuary "city of OS".
After hundred years researcher find out the secret of disaster is just hide in the ruins .
At this crucial moment the leader of OS were disappeared in an accident when explore the ruins .
cauce of it the situation between OS and enemy become more intensify the war is near .