 Due to centuries of unregulated nuclear warfare, a race of aggressive aliens known as the Furons has been rendered sterile, and forced to depend on cloning to reproduce. To help keep the genetic code of the Furons pristine, a trigger-happy Furon soldier named Cryptosporidium-137 is ordered to travel to 1950s Earth and steal genetic material from the indigenous sentient lifeforms. Along the way, he ll also have to investigate the disappearance of his clone predecessor, Cryptosporidium-136, uncover and foil a dastardly government conspiracy, and of course... "Destroy All Humans!"