Fugitive French crook Abel Davos (Lino Ventura) flees Italy with his partner Raymond Naldi (Stan Krol) and young family, getting as far as Nice before both Naldi and Abel's wife Thérèse (Simone France) are brutally gunned down by the gendarmes. With no time to grieve, Davos conceals his sons in a seaside boarding house and seeks help from crime boss Frangier (Claude Cerval), who dispatches hired hood Eric Stark (Jean-Paul Belmondo) to rescue the outlaw and his progeny in an ambulance and deliver them to Paris. En route, Davos and Stark become fast friends but the former soon learns that his old employers no longer have his best interests at heart, a realisation with bloody consequences for all concerned.
"I believed in the friendship of Abel Davos and Stark absolutely", said Jean-Pierre Melville after seeing Classe Tous Risques, a film that would greatly influence his own gangster-inflected oeuvre. "The two men's behaviour makes explicit their feelings, without either of them having to speak of their friendship. On the other hand, I was not able to believe in the friendship of [François Truffaut's] Jules and Jim, even though they speak of it often." Ouch.
The story was adapted from a book by Corsican ex-con José Giovanni, who also wrote the gritty novels on which Jacques Becker's Le Trou (1960) and Melville's Le Deuxième Souffle (1966) were based. One of Giovanni's ex-cellmates had been a certain Abel "The Mammoth" Danos, a hulking mobster and French gestapo during the Occupation, whom the aspiring author befriended by offering chocolate and contraband stamps in exchange for his life story.