The film is set in late 1977, where Jerry, Bill, Mary, and Denise are two couples out on the road in hopes of writing a book on offbeat roadside attractions. When the four meet Captain Spaulding, the vulgar but friendly owner of a gas station and "museum of the strange", they learn the local legend of Dr. Satan. As the four take off in search of finding the tree from which Dr. Satan was hanged, they pick up a young hitchhiker named Baby Firefly, who claims to live only miles away. Shortly after, the vehicle's tires burst in what is later seen to be a trap, and Baby walks to her family's house along with Bill. Only moments later, Baby's half-brother, Rufus, picks up the stranded passengers and takes them to the Firefly family house.