Description
Roger Marsh and Frank Stewart own a successful motorcycle dealership in San Antonio, Texas. Together with their wives Kelly and Alice, and Kelly's small dog, they leave San Antonio in a recreational vehicle (RV) for a much anticipated ski vacation in Aspen, Colorado. Along the way, they set up camp in a desolate meadow in central Texas, where Roger and Frank race their motorcycles together. Later that night, after their wives retire to the RV, the men witness what turns out to be a Satanic ritual human sacrifice a short distance from their campsite, across a river.
After being chased by the Satanists and barely escaping with their lives, they arrive in a small town and report the incident to Sheriff Taylor, who investigates but attempts to convince them that they probably only saw hippies killing an animal. Unbeknownst to the sheriff, Roger steals a sample of dirt stained with the murder victim's blood, intent on delivering it to the authorities in Amarillo, as he became suspicious of being driven to the crime scene without having had to offer any directions.
At the same time, while cleaning, the wives find a cryptic rune pinned to the broken rear window of the RV, and they steal books about occultism from the local library to further research the incident, unaware they're being watched by a man in a red truck. One of the books reveals that the ritual is what Satanists often perform to gain magical powers. As the foursome leaves town, the sheriff notices the red truck that begins to follow the RV, making it clear that he is either aware or part of the Satanic cult.
When the couples arrive at an RV park, Kelly feels she is being stared at by its residents while in a swimming pool and wants to return home. Nonetheless, she accepts a dinner invitation from another couple at the park. While at the restaurant/nightclub, Kelly again feels she is being stared at menacingly, this time by one of the musicians. When they return from dinner, the group discovers that Kelly's dog has been killed and hanged, causing them to immediately leave the park. Shortly afterward, they are forced to fight off two rattlesnakes planted in the RV by the cultists. The frightened Kelly and Alice scream and panic, causing Frank to accidentally drive into a tree and break the RV motor's fan before the snakes are killed.
The next day, Kelly's dog is buried, after which Roger and Frank repair the motor and find their motorbikes' tires, wheels and gas tanks cut. They purchase a shotgun and head towards Amarillo while being spied on by a steadily increasing number of cultists who seem to be networked throughout numerous small Texas towns. When Roger tries to place a long-distance call to the highway patrol, he finds one dead payphone and another with a "bad connection", and is told that long-distance service is down by a "big wind from up north".
The couples leave for Amarillo and are chased by the Satanists in various trucks, which the couples escape. Later, they encounter a staged school bus "accident" that Frank sees through, since it occurs on a Sunday, and none of the children appear hurt. The couples flee the scene and have a showdown with the cult members during another high-speed chase that pits their RV against numerous trucks and cars. Roger and Frank kill or injure most of the attackers, and the couples escape.
The RV's headlights were damaged during the chase, which forces the foursome to stop in a field at nightfall. They begin to celebrate when they pick up a radio signal coming from Amarillo. In the middle of their celebration, they hear chanting outside the RV and find themselves surrounded by cult members wearing black robes with hoods, including Sheriff Taylor and the couple with whom they had dinner. The film ends as the cultists light a ring of fire around the RV, trapping the couples inside while the chanting continues.
