Married couple Jeff and Amy Taylor (Kurt Russell and Kathleen Quinlan) are driving across the country from Boston to California. While driving through somewhere in rural New Mexico, they almost collide with another truck on the road. Jeff is later confronted by its driver, a hostile redneck cowboy named Earl (M.C. Gainey), at a gas station.
A short time afterwards, their car breaks down in the middle of the desert. Amy accepts a ride with a passing trucker named "Red" Barr (J. T. Walsh) to a small diner about five miles down the road to call for help, while Jeff stays with the car. Jeff discovers disconnected wires to be the problem with the car and drives to the diner, but no one there has seen his wife. When he catches up with Barr, the trucker swears that he has never seen her, or Jeff, before. Jeff hails a passing sheriff, but a brief search of Barr's truck is fruitless for Amy is nowhere to be found. Jeff tries to tell the sheriff (Rex Linn) that the trucker is lying about not remembering him or Amy, but the sheriff tells Jeff that he must go on his way.
Jeff drives with the sheriff to a local police station where he is advised to go back to the diner and wait for his wife. Jeff does so, only to end up meeting with Billy (Jack Noseworthy), supposedly a town simpleton and local mechanic, who says that he saw his wife come in with Red and leave in another truck driven by a cowboy. Billy then tells Jeff where they have taken her and Jeff gives chase, but is ambushed on the road by Earl. Jeff escapes by driving his car into a river. He exits the sinking car and floats down the river, later circling back around to where his attackers are salvaging it from the water. He is then found and knocked out by Billy.
Jeff awakes in the trunk of a car. Billy (no longer pretending to be mentally challenged) opens it and asks how much money Jeff has, which is then demanded in exchange for his wife, who is being held hostage. The two rednecks, Billy and Earl, remove Jeff from the trunk and bring him to their ringleader standing nearby, who happens to be Red Barr. Barr demands that Jeff withdraw a large sum of cash in exchange for Amy from a local bank in the nearby small town.
Jeff heads into the local bank to withdraw money and starts to confide in the bank manager about what is goind on, but is dissuaded by an unknown person entering the bank. Unsure of who is part of the conspiracy holding his wife hostage, Jeff stops talking. While the manager is busy with the transaction, Jeff takes some money ribbons and a letter opener knife from the manager's desk. After leaving the bank with the money, Jeff is contacted by Barr from a payphone to leave the town by walking, where he is picked up by Earl.
While gloating about how easy Jeff and his wife were to trick and implying that they intend to kill them anyway, Earl discovers that Jeff has wrapped stacks of $1 bills with a single $100 bill on the top and the bottom of the stacks, using the money ribbons he took from the bank manager's desk. Jeff then stabs Earl with the knife that he stole and forces him to reveal where his wife is. But just then, the same sheriff from the beginning of the film, seeing the truck being driven erratically, pursues and attempts to arrest both Earl and Jeff. Earl shoots the sheriff with a pistol concealed in his boot. Just as Earl is about to shoot Jeff, the wounded sheriff shoots and kills Earl. Jeff uses the Sheriff's radio to call for an ambulance and leaves behind the wounded sheriff to find his wife.
Although initially unsuccessful at finding Billy or his wife at the truck stop Earl mentioned, Jeff spots Red Barr, who is preoccupied with a telephone call to an accomplice. Seeing two State Troopers searching for a suspect in the shooting of the sheriff, Jeff manages to jump onto Barr's moving truck. After driving all night, Red Barr arrives at his family's farm where he greets his wife and teenage son, whom they address him as 'Warren'. Jeff hides in a barn and watches as Red, Billy, and a fourth accomplice, a towtruck driver named Al, take Amy from a compartment underneath the truck. They lock her in the basement under the barn and return to the house. Jeff also discovers that Red and his accomplices have apparently been preying upon unsuspecting travelers and truckers for some time now by stealing their money and killing them afterwords.
Jeff enters the house with a pistol and demands the barn keys from Red. Red's teenage son appears with a rifle and threatens Jeff, but accidentally shoots Al in the arm after Jeff knocks the gun from his hands. Jeff forces them to return to the barn. Red's wife opens the barn basement, and frees Amy from the box. Jeff locks everyone in the basement, then he and Amy steal a pickup truck and drive away after finding the keys for it. Billy, who escaped the house during the struggle, frees Red and his group from the basement.
As dawn begins to break, Billy, Al, and Red pursue Jeff and Amy; the former in cars and the latter in his truck. Jeff forces Billy's and Al's cars off the road, but Red follows them onto a bridge and tries to push the pickup truck over the edge. Amy's leg gets pinned underneath the dashboard, but Jeff escapes and fights Red in his truck, which then falls off the bridge and gets stuck on a barrier support. While Jeff hangs from the truck, Red tries to whip him off with a chain but Jeff grabs it and Red falls off the truck and to the rocks below. Jeff frees Amy and the two look down at the seemingly-dead Red, who then starts to move. Amy (clearly shaken and teeming with rage apparently stemming from sexual abuse at the hands of Red and his accomplices during her captivity) then pulls the automatic shifter on their pickup truck which has been holding Red's truck in place and it falls and crushes him. Relieved that their nightmare is over, the final shot shows Jeff and Amy standing in the middle of the bridge beside their damaged pickup truck looking over the guardrail at the bottom of the ravine at the burning truck as the image zooms out and fades to black.