Sometime in the distant future. Earth has been conquered by alien invaders.
The space pirate Harry Trent, who spent five years in a spaceship and thus did not notice the invasion from space, returns to Earth. His return becomes a bloody odyssey of horror. Gigantic creatures are rampaging on Earth, led by the alien invaders. They want to convert mankind into deadly fighting robots in order to take over the rest of the universe. But the experiments have not succeeded so far, most of the people became will-less zombies. Harry takes the side of a few rebels who offer fierce resistance to the cruel aliens. A final battle of superweapons begins.