A new day begins as Bobbi Torres, Britni Camacho, drives her 1977 Ford Mustang down the desert highway. Her sister Anna calls, urging her to leave Rhett, her abusive boyfriend. At a remote gas station, the sheriff, John Schwab, offers her a soda, which she declines. Anna calls again, comparing Rhett to their father, triggering Bobbi's anger. She speeds along the highway and is pulled over by the same sheriff, who accuses her of damaging his light-bar, demands $300, and takes her phone. Returning to the gas station, Bobbi finds the ATM broken and her card declined. The attendant buys her a beer and warns her about the sheriff, advising her to leave the county.
The sheriff ambushes Bobbi, shoots her car's lights and tire. He harasses her, takes her license, and demands payment. Bobbi escapes on foot after he forces her car off the road. At a diner, Bobbi steals change to call Rhett, who accuses her of having an affair with the sheriff and hangs up. She meets waitress Amy, Sydney Brumfield, but the relief is short-lived as the sheriff arrives, trapping her inside. She calls 911 and later her sister, but the sheriff returns her belongings, confusing her. Amy, fired for the money Bobbi stole, is offered a ride. Suddenly, a gunshot hits Amy, and Bobbi sees the sheriff's car approaching.
The sheriff ultimately corners Bobbi, frames her for murder, then manipulates a truck driver who is then killed. Bobbi speeds away, her car overheats, forcing her to abandon it at a scrapyard where she attacks the simple-minded attendant, Ed, Travis Lincoln Cox. Inside, while cleaning up, she discovers a wall of driver's licenses before the sheriff appears and confesses his crimes. As Bobbi tries to escape, Ed, the sheriff's brother, ambushes and knocks her unconscious. Bobbi awakens, bound and tormented by the sheriff and Ed, learning the sheriff is also Ed’s father, a result of Ed raping his abusive mother in the past. The sheriff rants about his mother, revealing the knife he holds is made from her jawbone, before offering Bobbi a twisted chance at freedom. Refusing his game, Bobbi provokes him, leading to a brutal act of mutilation. Awakening untied, Bobbi retrieves the jawbone knife and flees.
Bobbi stumbles across the desert until she reaches a road, where the sheriff's cruiser follows her, tracking her distance. Exhausted, she collapses, and the sheriff records her distance before offering water and a gun with one bullet. She loads the gun, seemingly shoots herself. The sheriff finds no head wound, only blood from her mouth, and Bobbi stabs him with a jawbone knife and steals his cruiser. The sheriff returns with the keys, but Bobbi unclips his holster and strikes him with a rock. She escapes in the cruiser, seeing him rise in the mirror. She turns to face him as he aims his gun. Bobbi drives toward him. He runs out of bullets since he forgot his clip in the car as she drives through him.
At the garage, she retrieves her tongue, packing it in ice for re-attachment surgery later on. Startled by Ed, she kills him with a wrecking bar. She then collects all the driver's licenses of past victims to use as evidence. When Rhett calls, she throws the phone away, finally rejecting his control, and drives towards the city lights as dawn breaks.
