Frank and Roger and their wives take off for Colorado in a recreational vehicle, looking forward to some skiing and dirt biking. While camping en route, they witness a Satanic ritual sacrifice, but the local sheriff finds no evidence to support their claims and urges them to continue on their vacation. On the way, however, they find themselves repeatedly attacked by cult members, and they take measures to defend themselves.

Director Jack Starrett claims he hired real life Satanists as cult-member extras.

Continuity: Just over an hour in Frank says to Roger that the oil cooler is "mashed up against the radiator, there". But there is no damage to the grill.