Aliens contact scientist Adam Penner to inform him that they have been living on the moon for twenty thousand years, unnoticed due to their invisibility, and have now decided to exterminate humanity unless all earthly governments instantly surrender. Penner, his daughter, a no-nonsense army major, and a squeamish scientist are trapped in an impregnable laboratory, attempting to discover the aliens' weakness. They are attacked from the outside by the aliens, who have occupied the bodies of the recently deceased.