In the year 3076, an unmanned space fleet started attacking the colony planets. The Grayzon System, which houses the central photon computer that integrates and controls the galaxy network on the mother planet Earth, was network-jacked by a terrorist group known as the Zakalite. The Galaxy Union and Colony Planets Fleet survivors assembled their forces and added the SA-77 Silpheed fighter ship to their fleet to counter-attack the Zakalite.