We don't have enough wars on Earth, and now there's a threat from outer space. An alien army is approaching the earth's orbit and their goals are quite clear and definite - the destruction of the planet. The earthlings were able to bring out only one ship, called the Space Guardian, to meet them. It is equipped with a powerful laser cannon that can fire indefinitely and has unlimited ammunition. One assault ship will be enough if you use it correctly. You need to deftly maneuver and shoot ahead of the curve so that the fired enemy missiles reach their target in Space Guardian.