Inherit the worldview of ZYCA at 1991 by SOFTSTAR.
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 .