Bobby, portrayed by Sean Penn, is a young drifter embarking on a cross-country journey in his Ford convertible. With his left hand bandaged, he's on a mission to deliver a gym bag brimming with cash to Los Angeles, a debt he owes. However, after the opening credits roll, disaster strikes when his car breaks down due to the radiator hose bursting. He finds himself stranded on the outskirts of Superior, Arizona, leaving his vehicle in the hands of the local mechanic, Darrell, played by Billy Bob Thornton. Darrell informs Bobby that repairs will take several hours, and Bobby opts to keep the gym bag while carelessly leaving a pistol in the trunk.
As he meanders through the quaint town, Bobby encounters Grace, an alluring Latina woman played by Jennifer Lopez, as she exits a hardware store with newly purchased drapes. Bobby seizes the opportunity to flirt and offers to assist her with her heavy haul. They exchange pleasantries, and when Grace inquires about his bandaged hand, he fabricates a story about a recent mishap. In a display of kindness, she invites him to her home for a shower to clean up.
The truth about Bobby's injury is laid bare during his shower: his "accident" resulted in the loss of two fingers, a punishment for his overdue debt. Once he emerges, he attempts to seduce Grace, but she rebuffs his advances. Just as he decides to leave, they share a kiss, only to be interrupted by Grace's husband, Jake McKenna, portrayed by Nick Nolte. Unaware of their marital status, Bobby is caught off guard when Jake retaliates with a punch.
While returning to town, Jake offers Bobby a ride, initiating casual conversation about Grace. Curiously, he provocatively asks Bobby if he would consider killing her for a price, revealing his disdain for her games. Bobby, taken aback, laughs it off, dismissing Jake’s bluntness as mere provocation.
Chaos ensues when Bobby is in a convenience store and witnesses a robbery involving two teenage thugs. They steal his gym bag filled with cash, but the shop owner heroically retaliates by shooting the robbers, resulting in most of Bobby’s money being lost in the fray. Left penniless and unable to pay the mechanic, Bobby desperately reaches out to various acquaintances for help, including the gangster he owes money to, who promptly refuses, fully aware of his whereabouts.
At a local bar, he encounters Jenny, a troubled teenage girl played by Claire Danes, who flirts with him. The scene escalates when Jenny’s possessive boyfriend, Toby N. Tucker, also known as T.N.T., played by Joaquin Phoenix, picks a fight with Bobby. Their confrontation is intervened by the town’s sheriff, Virgil Potter, portrayed by Powers Boothe, who warns T.N.T. and unwelcomingly orders Bobby to leave town as soon as his car is repaired.
Back at the mechanic's, Bobby finds out that Darrell has jacked up the price for repairs and has even taken his gun from the trunk. A confrontation erupts, rendering Bobby frustrated and angry—Darrell flatly refuses any form of payment other than cash.
When desperation mounts, Bobby recalls Jake's earlier offer and approaches him regarding the hit on Grace. Initially dismissive, Jake eventually reveals the grim details: he wants Bobby to take Grace out of town and stage her death to look like a suicide. Bobby is haunted by dark thoughts as he envisions carrying out the murderous plan but, instead, ends up becoming intimate with Grace. However, she abruptly halts their encounter, claiming she’s the "Queen of hot-and-cold."
In a shocking revelation, Grace shares her horrific past — she is not just Jake's wife but also his daughter, having endured years of sexual abuse. The twist thickens when Grace suggests that Bobby should actually kill Jake so they can take the stolen money. Although Bobby is hesitant, the urgency of his situation compels him to agree with her sinister plan.
Bobby’s attempt to escape reaches a tipping point when he manages to snag a bus ticket, but chaos reigns again when T.N.T. forcibly prevents his departure. In a fit of rage, Bobby fights back, brutally beating T.N.T. after Jenny bizarrely sides with her boyfriend.
Out of options, Bobby returns to Grace and finalizes their deadly pact to murder Jake. Under the cover of night, Bobby sneaks into Jake's home, only to be discovered mid-plan. As confrontation unfolds, Grace attacks Bobby, but her ulterior motive is to eliminate Jake. In a chilling turn of events, Bobby and Grace successfully overpower and kill Jake, discovering a staggering $200,000 in cash.
After paying the mechanic and retrieving his car, Bobby believes the worst is behind him until he is pulled over by Sheriff Potter, who has had a clandestine affair with Grace. Under threat of arrest, Grace surprises both of them by killing the sheriff and tying Bobby into the ensuing chaos, as they shove both bodies into the trunk.
The duo then embarks on a grim journey to dispose of the bodies until Grace cunningly pushes Bobby over a cliff. Despite the fall not being fatal, Bobby finds himself critically injured as Grace reveals her treachery, openly expressing her greed and the truth about her mother’s death — she had killed her too.
As Grace attempts to leave, Bobby locks her out of the car, leading to a deadly confrontation where he strangles her, only to receive a gunshot wound in the process. Despite his injuries, Bobby painfully scales the cliff, only to find his misfortunes continue as his car experiences yet another breakdown.
Laughing maniacally at the absurdity of fate, he gazes up at the azure sky, realizing he is doomed to perish in the desert wasteland, abandoned and alone.
