In a French-speaking port in Northern Europe, Laure, Isabelle Adjani, is an aimless young woman who goes to visit her boyfriend Samson, Gérard Depardieu, a washed-up boxer. While posing for photographs for an interview, Samson is offered a huge payout if he lies about having had a homosexual relationship with a politician who is a candidate in the upcoming election. The smear campaign is plotted by political rivals with ties to gang members. Although hesitant, Laure pushes him to take the offer, hoping the money will fund a better life elsewhere.
The campaign's organizers quickly propose a counteroffer: if they simply leave the country, they will receive an equal amount of money. Laure returns to her home in the city’s red-light district, where her roommate Nelly, Marie-France Pisier, works as a kind-hearted prostitute and runs a show-window business. Nelly is protective of her friend and tries to persuade Laure to stay; a quarrel breaks out when Laure contemplates leaving. Jules, Nelly’s husband Claude Brasseur intervenes; after discovering the money hidden in Laure’s bag, Nelly lets Laure leave but insists Jules accompany her to the train station.
At the station, Samson is shadowed by two hired assassins. Laure buys train tickets and hides the money in the station’s lockers, but the lovers are forced to part ways. She waits for him at a local diner, but falls asleep and ends up spending the night there. The next morning she is awakened not by Samson but by one of the killers who demands the money. As Laure runs, Samson appears on the snowy street and is immediately shot by the assassin; he dies as a train barrels toward the station.
Samson’s killer, a brunette who bears a striking resemblance to him, pursues Laure and the money. After returning from helping the police with the murder investigation, Laure confronts the killer, who is unexpectedly moved by her resolve. Walt, the editor of the newspaper that would have run the scandal, gets involved in the murder case, aided by Antoinette, his assistant and a reporter secretly in love with him. Jean-Claude Brialy as Walt and Hélène Surgère as Antoinette push the investigation forward, with Gauthier, the gang leader, drawn into the struggle as well by Julien Guiomar.
The killer hides from both rivals and the police. Nelly briefly offers him shelter while continuing her own life, and, in a moment of theater, performs la radical—a dance and song number—but he remains focused on his own survival. Antoinette and Walt invite Laure to dinner, and they watch a torch singer perform, a moment that deeply moves Laure. When she returns home, the killer is still waiting in the shadows. Laure challenges him, insisting that he earn her love only if he can resemble the boxer he killed. He agrees to reinvent himself in Samson’s image, and the two decide to seize the money and flee the city together. On election night, as the results come in and celebrations erupt, the couple escapes aboard a liner, while the gangsters shoot Walt by mistake instead of Samson’s killer, leaving the political intrigue unresolved as they slip away into the night.
