A long period of peace has deprived the earthlings of their instinct to wage war. The Federated Government, greatly concerned regarding this ever increasing dangerous situation, developed a Gain Ground simulation system in the year 2348 in an effort to instigate their ever waning fighting spirit However, suddenly without warning, the Supercomputer went berserk and took many of the citizens as hostages. In order to rescue the POWs, three of the bravest warriors were urgently dispatched to go forth into the deadly Gain Ground.