Laine, a drifting wanderer, drifts through a quiet morning after dozing in her car in the parking lot of a small motel. When she wakes, she hides a personalized money clip and is soon welcomed by Luanne, the motel’s owner, who offers Laine a free meal as a kind of first gesture. As a local police officer named Gault arrives on the scene to fix Laine’s flat tire, he informs her that a brutal murder has rocked nearby Flagstaff. In a small, almost incidental moment of kindness, Laine makes a coffee for Gault as a favor for Luanne. This simple exchange plants the seed for a new possibility: a job.
On Gault’s recommendation, Luanne offers Laine work as a waitress in the motel’s diner. Laine declines the offer at first and instead asks to be given a free room for the night. Offended by the rejection, Luanne relents and accommodates her. Later, Laine slips into the adjoining room, stealing a necklace and a bottle of sedatives. The couple in the other room returns, forcing Laine to hide in a closet and listen as they discuss a completed heist, a detail that unsettles her but also confirms the danger surrounding her.
Convinced that the day’s drop-off will originate at the motel, Laine apologizes to Luanne and once again asks for a job. When Luanne seems hesitant, Laine hints that she might return to an abusive boyfriend, and this threat convinces Luanne to hire her. Inside the diner, Laine meets the other guests: Lee, a taciturn man; Flynn and Gloria, the couple from the neighboring room; and Eddie, Gloria’s younger brother. When Gloria becomes flustered and reveals that her necklace has vanished, the group scrambles to soothe her, and Gault steps in to mediate. Worries about being discovered add to the tension, and Laine slips away to return the necklace. Before leaving, Gault flirts with Laine, who bluntly rejects him, an act that leads Gault to retaliate by slashing her tires.
Laine experiments with sedatives, practicing on a guest by slipping the drug into a drink and watching him pass out. That night, Flynn and Gloria celebrate their supposed luck with drinking and revelry, while Laine attempts to slip sedatives into their beverages. Lee returns to the diner in a fury, slamming the door on the party and demanding to know who Laine truly is. Luanne intervenes, but Laine’s fear and defiance cross lines when she admits to killing a man in Flagstaff who had attempted to rape her. Lee recognizes the money clip as belonging to the murdered politician and, for now, lets her live. He even agrees, with Luanne’s persuasion, to give Laine a small cut of the night’s heist.
Back at the diner, Laine resumes serving coffee that has been laced with sedatives. Eddie resists the drink, but he ends up ingesting a smaller dose from a prior serving. As the group drifts into unconsciousness, Laine drags them out of sight and prepares to make a clean escape once the courier arrives with the money. Gault returns, offering an apology for his earlier behavior and, in a moment of flirtation, is briefly able to engage with Laine, though he ultimately declines her offer of coffee. The courier arrives and delivers the money, but Eddie wakes, knocks Laine unconscious, and leaves with the cash.
Laine accuses Eddie of drugging everyone and absconding with the money. Lee insists she accompany the group in pursuit. They trace Eddie to a crashed car and follow bloody tracks to a confrontation where Gloria defends Eddie and Lee kills both Gloria and Eddie. Luanne, seizing Gloria’s necklace, comes under Lee’s pressure, and Laine assists in moving the bodies into the trunk. The discovery of the courier’s body makes them fear Eddie’s hand in another murder, which Flynn confirms when he shoots Lee and assaults Luanne. Laine retrieves Lee’s pistol and holds Flynn at bay, but Luanne disarms her, kills Lee, and takes the gun for herself.
When the group returns to the diner, Luanne’s suspicions about Laine deepen as she finds the bottle of sedatives. Laine manages to turn the moment to her advantage and bludgeons Luanne to death. Just then, Gault returns, calling for backup and claiming the money remains unrecovered. In a private moment, Laine suggests that Gault himself might be the person who killed the corpse found in Eddie’s car. With that fragile dynamic in place, Gault allows Laine to leave on the condition that she will corroborate his version of events. The film closes on a tense note, with Laine walking away into the night, the motel and the money’s fate hanging in the balance and Gault’s assertion remaining a possible, uneasy truth.
