Year 2947. Earth invaded by evil clan of k'caj Yenrut galaxy. You Galactic Commander Frank Drexor. United States space protection task entrusted to you to protect the most important sector of the galaxy from the invaders. k'caj technology much more advanced than Earth technology. Some of the ships were hauling beams. Others are equipped with subspace energy destroyers. Disintegrating create energy barriers, which actually cause the shots from guns to reflect back to you! If your mission has failed, k'caj gain control of this important sector of space, allowing them to maneuver their troops and equipment more efficiently and gain a greater foothold in the battle for the planet. It certainly would be a disaster for the people of Earth. Their fate is in your hands!