Two backwoods brothers ambush a landing party of extraterrestrial beings who have crash-landed on their swampland property. The brothers kill the males and take the alien female into captivity. They secretly keep her prisoner for months in their basement. She becomes impregnated with the spawn of one of the Brakk brothers and escapes into the swampland where she gives birth to a monstrous creature that exacts crowd-pleasing revenge on the sadistic brothers.