A young Frenchman, Thomas Chanard, an employee in a New York restaurant, witnesses a murder committed by a local mafia boss who slays his mistress in gallant company and his companion in misfortune. He decides to leave the country early and rushes back to France. Alas for him, a killer is dispatched on the spot where our boy poses many problems by reviving an old love, today married with a scoundrel. At the same time, a New York policeman arrives in the small hotel run by the mother of our fugitive.