To escape his captors an industrial spy hijacks a space shuttle only to find the controls malfunctioning. Catapulting through outerspace, he sights alien battleships approaching earth. Many years later when the arc of his flight path returns him to earth, he discovers the planet is completely under alien domination, totally devastated by thermo-nuclear battles. Desperate and alone, he searches for any human existence. Finding a group of survivors, together they fight the aliens to save mankind.

The sequel to 'Galaxy Destroyer' which finds our hero Harry Trent wandering Earth's post-apocalyptic landscape full of mutants, monsters, and fragmented human tribes. Harry's attempt to help a young girl rescue her sisters, leads him to a group of armed mutants led by a human madman attempting to breed them and take over the world.