Clips from assorted television programs, B-movies, commercials, music performances, newsreels, bloopers, satirical short films and promotional and government films of the 1950s and 1960s are intercut together to tell a single story of various creatures and societal ills attacking American cities.
Cinco extraterrestres vienen a la Tierra con el fin de conquistarla, haciendo uso de ella como granja donde pasten sus rebaños de Gargons. Pero uno de ellos no está dispuesto a seguir asolando planetas e intentará salvar a nuestra especie.