Big Bob and Ethel Carter, their son Bobby, daughters Lynne and Brenda, Lynne's husband Doug and their baby granddaughter are on their way to California. Big Bob wants to visit an old silver mine once owned by his family. When they stop for gas at a remote station, Fred the owner warns them about going off the beaten tack telling them it's way too dangerous. Big Bob is stubborn and pushes on but when the car breaks down, they soon realize they have to deal with cannibalistic mutants living in the nearby mountains. Few will survive.—garykmcd