A group of scientists are killed by a mutant named Pluto (Michael Bailey Smith). Later, Bob Carter (Ted Levine) and his wife, Ethel Carter (Kathleen Quinlan) are traveling from Cleveland, Ohio to San Diego, California for their silver anniversary. With them are their teenage children Bobby (Dan Byrd) and Brenda (Emilie de Ravin), their eldest daughter Lynn (Vinessa Shaw), Lynn's husband Doug Bukowski (Aaron Stanford), Lynn and Doug's baby daughter Catherine (Maisie Camilleri Preziosi), and their German Shepherds Beauty and Beast.

In the New Mexico desert, they meet a gas station attendant named Jeb (Tom Bower), who tells them of a short-cut through the hills. After taking the supposed short-cut, their tires are punctured by a hidden spike strip. Doug and Bob go look for help, while the rest of the family stays behind. After the attacking of thier families they are survived from the mutants.