For the last 200 years, the major energy is Di-Planium which is sourced on the fourth planet of the Krellis System defended by ten levels of defence called the Diagon Network. Your task is to defend the Network from an invading alien force by destroying all their ships on each level. The game is a top view single screen shooter where you move around the screen destroying the aliens, and although you can move in various directions, you can only fire forwards. On the outside of each screen are also aliens that fire inwards and if you are hit by their weapons or any ship then you lose one of five lives. Destroy all the aliens and you move to the next level. Before you start a game you can select your entry level (0-9).