In the small town of Jefferson Valley in Downstate New York, a number of civilians start going missing over the course of a few weeks. One day, a man covered in blood stumbles into the bar screaming before abruptly collapsing and dying. During the investigation, local scientist Roy Anderson discovers that the man's blood cells have been reproducing at an impossibly fast rate. Later that day, a strange man dressed as a farmer approaches the house where Roy lives, only to be chased off into the woods by Roy's dog Buster. The farmer beats Buster to death with a cane in self-defense, but unknowingly drops a mysterious antique key whilst disposing of the dog's body. The next morning, Roy's daughter Jenny finds Buster's body strung up outside their front door. Jenny's fiancé Don runs off into the woods to try and find the culprit, and finds the key the farmer had dropped.