The Carter family are on vacation and are travelling from Ohio to California. Along for the trip is Big Bob Carter (Russ Grieve), his wife Ethel (Virginia Vincent), their children Bobby and Brenda (Robert Houston, Susan Lanier), the oldest daughter Lynne (Dee Wallace), her husband Doug (Martin Speer) and their baby Katy.
The Carter’s are travelling by car – a station wagon with a trailer pulled behind. While passing through Nevada Big Bob wants to take a short cut through some dirt roads. Stopping at a gas station owned by an old timer named Fred (John Steadman) Big Bob asks directions. Fred warns them not to take the dirt road.
Bob ignores Fred’s advice and takes the road. Soon they crash and are stranded. The dogs Beauty and Beast are nervous. Bob walks back to the gas station while the rest of the family wait.
At the gas station Fred tells Bob about Fred’s son Papa Jupiter (James Whitworth). Jupiter was evil and murderous and Fred tried to kill him but failed and Jupiter went out into the hills with a prostitute called Mama and started his own family. Mars(Lance Gordon), Mercury (Peter Locke) and Pluto (Michael Berryman) along with Ruby (Janus Blythe). Jupiter and his family hunt down travelers, murder them, steal their stuff and eat them. Just a happy family of cannibals living in the woods and Bob drove his family straight into their clutches.
Jupiter kills Fred and takes Bob hostage. Meanwhile Bobby finds Beauty dead and tries not to tell the family about it. Then Jupiter and his clan show up with Bob tied up.
Wes Craven had started to make a name for himself with his first feature film The Last House on the Left and this film would start to secure his place as a master of horror. Craven loosely based the movie on the 16th Century Sawney Bean legend but updated it for a more modern take. There was a really bad sequel made a couple of years later by Craven who would quickly disown it and this film was remade in 2006.