Jim Halsey (C. Thomas Howell), a young man delivering a car from Chicago to San Diego, spots a man hitchhiking and gives him a ride. The man, giving his name as John Ryder (Rutger Hauer), is a brooding, soft spoken man; when Jim passes a stranded car, however, Ryder's personality suddenly shifts. Ryder calmly states that the reason the car is stranded is because he murdered and mutilated the driver, and he intends to do the same to Jim. Ryder produces a switchblade knife and taunts Jim for several moments, before Jim realizes Ryder never put on his seat belt and that the passenger door isn't fully closed and knocks him out of the car.Relieved, Jim continues on his journey, until a station wagon carrying a family on vacation passes, and Jim is horrified to see that Ryder has hitched a ride with them. Jim attempts to signal the family, but ends up nearly totaling his car; when he finally catches up to the station wagon, Jim discovers the entire family has been horribly mutilated by Ryder.The movie shifts into an elongated chase sequence, which finds Jim trying to flee Ryder both on foot and in his car, to no avail; wherever Jim runs, Ryder finds him: It seems that Ryder, impressed with Jim's show of bravery by knocking him out of the car, has decided that Jim is the man who is finally going to put his killing spree to an end.Jim then finds Ryder at an abandoned gas station. Ryder knocks down the gas pumps with a pickup truck and then lights a match. Both cars drive off and the gas station explodes. Jim retreats to a roadside diner, where he meets a pretty young waitress named Nash (Jennifer Jason Leigh) and calls the police. She then serves him a cheeseburger and french fries. He eats these in solitude, until discovering that one of the fries is a severed finger. Realizing that Ryder is nearby, Jim attempts to flee, but is stopped by the police who promptly place him under arrest, mistakenly thinking that he might be responsible for the dead bodies found by the side of the road. At some point, Ryder pick-pocketed Jim, and placed his wallet at the scene of a murder. Jim is taken to a local jail, booked, and placed in a cell.Sometime later in the day, Jim awakens from a nap to find the police station eerily quiet and his cell door open. Jim slips out to discover the bodies of three murdered policemen. Jim panics, steals a gun and runs from the station house as five police cars arrive.Jim comes to a pay phone and sees two cops pull up. Knowing that Ryder has framed him, Jim points his gun at them and takes the troopers hostage, forcing them to drive him away from the scene. He forces the police officers to get him in touch with the captain, and Jim pleads his case. The captain suspects that Jim is telling the truth, and asks Jim to come meet him. Jim agrees, but just then, Ryder pulls up alongside the car, kills the cops with a revolver, shoots out the radio, and drives away.Jim wanders across the desert to a diner and is confronted by Ryder. When Jim asks Ryder why he's pursuing him, Ryder only replies that Jim should know, then calmly reaches across the table and sticks two pennies over Jim's eyes (an ancient funeral ritual performed on corpses, so that their souls could pay Charon to carry them across Styx to the land of the dead). Jim is left terrified and alone with the pennies on his eyes - and a handful of bullets that Ryder left him for his gun. Jim attempted to shoot Ryder, but only to find that his gun has no bullets.Jim leaves the diner and sneaks onto a Greyhound bus. He then sees that Nash is on the Greyhound. He pulls Nash into the bus's bathroom and convinces her that he's innocent.Before the two can act, the police stop the bus and attempt to arrest Jim. But the hot-tempered Trooper Hancock (Henry Darrow) means to kill Jim because one of the policemen murdered by Ryder was his brother. Nash takes Jim's gun and pulls it on the two officers, and she and Jim flee in a police car. They're chased by two more police cars and Jim is forced to blow out their tires and cause them to collide with one another. Then a police chopper arrives and starts taking pot shots at Jim. Then Ryder pulls up, shoots the chopper down and drives away.The pair hide out in a roadside motel, but while Jim is taking a shower, Ryder breaks into the room and kidnaps Nash, dragging her to a truck stop parking lot where he ties her between a Mack truck and its trailer, threatening to tear her in half if he doesn't speak to Jim. The police, now convinced of Jim's innocence, enlist him to try to negotiate with Ryder. In the cab of the truck, Ryder demands that Jim shoot him. Jim refuses, saying that if he were to shoot Ryder, Ryder's foot will slip from the clutch, killing Nash anyway. Furious, Ryder insults Jim and then shifts both the clutch and the accelerator - the truck screams forward, killing Nash. Police swarm the truck and arrest both Ryder and Jim.At the station, the authorities are bewildered, unable to find any information on Ryder: He has no social security number, no driver's license, no indication that he has ever existed. All that the police can determine is that Ryder is a serial/spree killer and a threat which the local department cannot handle, and arrange to have him transported for holding at a state prison. Before Ryder is placed into a transport van, the police allow Jim to see him in the interrogation room. Ryder seems pleased to see Jim and touches his hand. Jim responds by spitting in Ryder's face.The police cover Ryder in shackles and chains and place him in the back of a prison bus, escorted by multiple officers. As Jim is loaded into a police car to be taken to his family, he finally decides to murder Ryder. Jim steals Captain Esteridge's gun and hijacks the squad car, chasing the prison bus. As Jim pulls up on it, the back doors fly open, to reveal the entire police escort murdered and a bloody, still partially chained Ryder clutching a shotgun. As the van veers out of control, Ryder leaps off the back of the van and crashes through the window of the police car Jim is driving. Jim slams on the brakes, throwing Ryder off; the sudden braking, though, causes the police car to stall, and a bloody Ryder lifts himself from the highway, picks up his shotgun, and begins firing it into the police car.Jim avoids the damage of the blasts by lying sideways, repeatedly turning the ignition key and pumping the gas pedal in an effort to restart the car; he eventually restarts the car, and slams it into Ryder, throwing him off the side of the highway. Jim slips out of the car, picks up the still-loaded shotgun, and inspects Ryder's corpse. Satisfied that Ryder is dead, he turns around and heads back to the police car when he hears movement behind him. As he stops, Jim is not surprised that Ryder is alive and standing up. Ryder smiles at Jim and throws his shackles down at Jim's feet. Jim responds by emptying the remaining shotgun shells into Ryder's body, at last killing him, and leaving Jim alone in the desert to light up a cigarette and watch the sun set over the horizon.