It's the 31st Century, and science and technology have progressed to the point that the human race is approaching perfection: no war, no poverty, and no conflict. With nothing to worry about, the human race seems destined to live forever in harmony; but what if the Earth were to come under attack? At this point in time, people do not know how to cope with problems or conflicts, and have completely lost their survival instincts. In response to this, the United Earth Government has created the Gain Ground system, a war simulator that would help humans rediscover these lost instincts. After several terrible malfunctions, the creators have become prisoners in their own creation. Now it's up to you and two courageous comrades to go into the Gain Ground system, rescue your fellow humans, and destroy the system. You'll battle through different periods in history as you revive your survival instincts, and try to stay alive while doing so!