The Union has defeated the Masters and can now confront the Grillen, who have invaded more than a million planets in M87 and are threatening to invade the Union. While the Union was fighting for survival against the black monsters in a distant galaxy, the Grillen have begun building warships that are invincible. They are immune to the Rover’s beams and the Union’s force fields are no barrier to their destructive power. No one knows where the Grillen suddenly acquired this new and deadly technology but an answer must be found quickly before the full production of these Grey Ships leads to the Union Fleets being overwhelmed.

Time is running out and the future doesn’t look good. The only chance of success is going to be left in the ten arms of a former Master and there is huge doubt he can be trusted. The action becomes fast and furious when the source of the Grillen Technology enters the war.