Technology and civilization continue to develop, the earth ’s resources are depleted, and war and chemical experiments have left the earth with almost no clean land. Most of humanity has migrated to Mars and colonial satellites, and you can only hide in the only one because you do n’t have enough money. In the small village, and at this time a large wave of creatures polluted by chemical and radiation are approaching, you pick up the only weapon that can purify the polluted creatures, the great sword!