Henry is a psychopathic drifter who moves across the country, leaving a trail of murder in his wake. He eventually arrives in Chicago, where a routine stop in a diner and a late visit to a liquor-store owner become part of a chilling pattern of violence against the vulnerable. As he roams, he takes life indiscriminately—men, women, and even children—driving his brutal spree to new, shocking extremes.
Otis, Henry's prison friend, picks up his sister Becky at O'Hare International Airport and brings her back to the apartment Otis shares with Henry. That night, Becky presses Henry about the murder of his mother, a crime that landed him behind bars. Henry explains that he stabbed his mother, a claim he presents as the result of childhood abuse and humiliation, sometimes contradicting himself by suggesting he shot her or killed her with a bat. Becky reveals a troubling family history of her own, confessing that her father raped her as a teenager. Henry responds by acknowledging a distaste for sexual violence against women and, in a surprising moment, forms a protective bond with Becky. When Otis makes an incestuous advance toward Becky, Henry reacts with a fierce threat and forces him to promise not to pursue it again. Becky’s feelings begin to tilt toward Henry, though he remains repelled by her overt romantic interest.
The following day, Becky finds employment at a salon, while Henry and Otis venture out at night and kill two prostitutes—Henry ending their lives by breaking their necks. Otis is deeply shaken and questions Henry about this murderous lifestyle, yet Henry tries to recruit him into a shared philosophy of murder, arguing for a relativistic view of killing. Otis worries about police scrutiny, but Henry reassures him that everything will work out.
Their spree intensifies when they visit a fence to replace a broken TV. The fence ridicules their poverty and refuses to sell them illicit goods, yet Henry seizes the moment to satisfy his bloodlust: he stabs the man with a soldering iron, Otis assists by choking him with an electrical cord, and Henry then crushes the man with a television. Otis, encouraged by Henry, grins as he plugs in the damaged TV and watches the man die by electrocution. The two escape with a high-end TV and a camcorder, returning home undetected.
A violent catalyst follows when Otis is punched by a teenage boy after attempting to sexually assault him while selling marijuana. Henry urges Otis to drop the grudge for fear of being recognized by witnesses, especially since Otis has already been seen nearby. Emboldened by the earlier kills, the pair embark on a broader murder spree, setting a trap on Lower Wacker Drive by posing a broken-down car to lure victims and then shooting a man who stops to help. Henry counsels Otis to vary the method of each murder so authorities won’t link them as a single killer. He stresses the importance of staying mobile; by the time police close in, they will have already moved on.
Henry also notes he will have to leave Chicago soon. Later, they watch a tape of a home invasion in which they murdered a suburban family of three, a scene Otis uses to begin molesting the mother’s corpse until Henry objects.
Becky, hearing that her ex-husband has been jailed for murder, quits her salon job to return home to her daughter. Meanwhile, Otis and Henry argue after their camcorder is damaged during Otis’s attempt to film female pedestrians from Henry’s moving car. Otis goes for a drink while Henry returns to their apartment. Becky outlines her plans, and the trio agrees to go out for steak. Becky attempts to seduce Henry, but Otis interrupts. Henry heads out to buy cigarettes and catch his breath. On the way back, he encounters a woman walking her dog and briefly contemplates murder, but decides against it.
When he returns, Henry finds Otis attempting to rape and strangle Becky. A violent confrontation ensues, and Otis gains the upper hand briefly. As Otis readies to kill Henry, Becky intervenes by stabbing Otis in the eye with a comb. In a brutal turn, Henry seizes the weapon and murders Otis, then dismembers the body in the bathroom.
The two retreat from Chicago, dumping bags of Otis’s remains into the river and leaving town. Henry proposes a trip to his sister’s ranch in San Bernardino, California, promising Becky they will send for her daughter once they arrive. In the car, Becky confesses that she loves Henry. > "I guess I love you too," Henry replies. They check into a motel for the night. The next morning, Henry departs alone, leaving Becky behind. He stops by the roadside and discards Becky's blood-stained suitcase in a ditch, hinting that her remains lie inside, and drives away into an unknown future.
