Two backwoods brothers, Petus and Pervis Brakk, ambush a landing party of extraterrestrial beings on their swampland property collecting Earth plant samples for study. The brothers kill the males and take the alien female into captivity where they torture and abuse her. They secretly keep her captive for months in their basement cellar. She becomes impregnated with the spawn of one of the sadistic brothers and escapes into the swampland. Before she dies, she gives birth to a monstrous, half-alien, half-human egg-shaped, creature with extraterrestrial powers, HUMPTY DUMPTY.
In the meantime, a smart Southern sheriff becomes suspicious after reports come into his office about a UFO seen by people from the small town. He ultimately solves the case, but not before Humpty has taken crowd-pleasing bloody revenge on the Brakk brothers for their unspeakable acts against his mother.