A young man, named Ash, takes his girlfriend Linda to a secluded cabin in the woods where he plays back a professor's tape recorded recitation of passages from the Book of the Dead. The spell calls up an evil force from the woods which turns Linda into a monstrous Deadite, and threatens to do the same to Ash. When the professor's daughter and her entourage show up at the cabin, the night turns into a non-stop, grotesquely comic battle with chainsaw and shotgun on one side, demon horde and flying eyeball on the other.
