Saturday evening. A dance in a small town near Paris. A fight breaks out. An Arab boy has stolen a wallet from a Paris boy. The culprits are arrested and released the next morning. But on the way back to Paris on the train, three of the boys just released lynch an Arab, pusch him off the moving train and then make their getaway... The investigation of this disgusting crime reveals the atmosphere of a small town where racism is born of insecurity, fear and hatred. Thanks to a brave womanUs testimony, Inspector Couturier breaks down all unwillingness to talk by using forceful, spectacular strategy.