Late one night, a woman is killed while babysitting a young boy; the killer then kidnaps the boy. A few months later, a man and cleaning woman are killed at a motel in Amarillo, Texas. Amarillo's sheriff Buck Olmstead, R. Lee Ermey, is up for reelection. Both he and his opponent, police chief Jack McGinnis, William Fichtner, strive to solve a sprawling murder case before election day. Meanwhile, hitchhiker Lane Dixon, Jared Leto, is picked up by Bob Goodall, Danny Glover, an affable drifter driving a white Cadillac Eldorado.
FBI special agent Frank LaCrosse, Dennis Quaid, arrives in Amarillo and explains that an elusive serial killer is behind the killings. Olmstead learns that LaCrosse was taken off the case because the kidnapped boy is his son, Andy LaCrosse, Ian Nelson. LaCrosse brings a cryptic note from the killer, a message that taunts the FBI’s persistence and hints at the means to locate his son. The note includes clues that will become clearer as the investigation unfolds. Reluctantly, LaCrosse teams up with the local sheriff’s department, and Olmstead worries that cooperating with a suspended agent could jeopardize his own political future. The tension between federal and local authorities adds a wary edge to an already delicate situation.
Dixon soon becomes a prime suspect, but with LaCrosse in pursuit, the truth points to Goodall as the killer. At a mechanic’s shop where his car has been repaired, Goodall pulls a knife on the mechanic—an old friend and former coworker—after noticing a state trooper eyeing the white Cadillac. Unseen by Dixon, Goodall murders his friend, severing any link that might connect him to the car. As Dixon and Goodall ride together, a surprising rapport forms between them; Goodall shares stories about his son and asks Dixon to look after the boy if anything happens to him. Dixon agrees, and Goodall provides the boy’s address, planting a clue that will later prove pivotal.
Authorities discover that the driver of the white Cadillac at the latest murder fits Dixon’s description, yet no one names Goodall aloud. Roadblocks overlook the mountain roads, which become nearly impassable after a violent blizzard seals the area. Goodall’s overconfident driving on those treacherous backroads sends the car careening off a cliff. Dixon is flung into the snow and, with a daring move, climbs through the passenger window to cut Goodall free. In a display of gritty grit and mutual dependence, Goodall later saves Dixon from a near-fall, even as their uneasy alliance continues to drift toward a grim end.
The pair walk toward a small town with plans to catch a train westward. Dixon overhears locals saying the murderer is driving a white Cadillac. His suspicions flare, but they’re briefly eased when the newly elected Sheriff McGinnis issues a radio announcement that the killer has been arrested; the vehicle in question is linked to Goodall, who is presumed innocent in the eyes of the authorities for the moment. Nevertheless, Goodall and Dixon reconcile long enough to board a train, sharing a ride with Tex Monroe, Sandy Ward, another friend of Goodall’s. Tex’s presence adds a tense, uncertain dynamic to the journey, as suspicion lingers in the air.
LaCrosse follows the trail, guided by the cryptic clues Goodall has left behind. After a car crash, he travels on foot to intercept the train and manages to jump onto the moving carriage. Dixon knocks Goodall down just as LaCrosse reaches the railroad car, and the climactic confrontation erupts. Dixon, insisting on his innocence, is confronted by Goodall, who taunts LaCrosse and presses his knife toward the young man’s throat. A brutal struggle spills onto the snow-scraper, a large metal beam on the side of the train. Hanging on, Goodall tries to force LaCrosse to kill him so he can locate his son, but fate intervenes when Goodall’s grip slips. He slips away, laughing at the last moment, and tumbles backward down the snow-swept slope, fatally impaled by a tree branch.
Left battered but alive, LaCrosse tends to Dixon, who cannot speak because of a throat wound. In a final, crucial moment, Dixon realizes that Goodall’s earlier clues point to the boy’s location. He writes the address on the train car’s floor with a felt-tip pen, directing LaCrosse to the neighbor’s yard where his kidnapped son is waiting. LaCrosse discovers Andy LaCrosse, Ian Nelson, playing in the neighbor’s backyard, bringing a quiet, devastating closure to a case defined by tension, deception, and a father’s desperate pursuit of his child. The hunt ends not with a clear confession, but with a hopeful reunion, tempered by the scars of what was endured in the snow-choked night and the relentless pursuit that followed.
