Un homme d'honneur

Richard Altman, an upstanding and respected judge, sees his life turned upside down when his son Lucas commits a hit-and-run, leaving a motorcyclist for dead. Richard pushes his son to turn himself in, but realizes that the victim, Mathieu Riva, is none other than the son of Bruno Riva, a drug lord Richard recently sent to prison. Richard understands that Lucas would be signing his death warrant by turning himself in to the authorities. He decides to make it seem as if his car was stolen, and seeks the help of his best friend, Fred. Fred assigns a young delinquent, Kevin, to make the car disappear. Yet Kevin is stopped by police at the wheel of the vehicle. When Richard learns that the young man has been taken into custody, he entrusts the case to the idealist young lawyer Leila Diene. However, the situation becomes more complicated when Commissioner Laure Constantine, with whom Richard had a passionate affair before the tragic suicide of his wife a year earlier, is chosen to investigate the hit-and-run with the help of Investigating Judge Behrami, with whom he is competing for a prosecutor's position.

Whilst being questioned about the discovery of evidence linking his car to the hit-and-run, Richard manages to manipulate Commissioner Laure Constantine into following a false lead. Laure ends up believing that Ludovic Lebrun, a dirty cop who hates Richard, and Driss Adibi, one of Riva's former dealers who is trying to go out on his own, are responsible for Mathieu Riva's accident. Laure confronts Kevin to confirm this hypothesis, but he remains silent. Knowing that he is in trouble, Richard manages to get himself appointed to the case so as to make sure he's up to date. With the help of Fred, to whom he ends up confessing everything, he will try to bribe Kevin to finger Samir Belaid, a henchman of Driss Adibi, as the person who paid for the accident. The Riva clan, determined to take revenge, has Lebrun kidnapped and murdered. Simon Riva, Mathieu's younger brother, is determined to conduct his own investigation to find the real culprit. He goes back to the scene of the accident with a friend, and they find a Ventolin inhaler, left by Lucas the day of the accident…

Lebrun's charred body is found. Laure does not exclude the possibility that Driss Adibi is responsible, and wants to charge Kevin to make him talk; Richard tries to dissuade her from doing so. He invites her to the restaurant by feigning a rekindling of their romance. Meanwhile Lucas, who is still rattled by the accident, gets closer to his teacher Gabrielle. Confusing her kindness for attraction, he kisses her. Gabrielle is shocked and pushes him away, but it's too late because Lou, a student who is secretly in love with Lucas, has filmed everything. Richard manages to clear up the situation with the principal. In the midst of all this, Fred manages to persuade Kevin to accuse Belaid, Driss Abidi's right-hand man. Following his mother's advice, Simon Riva brings the inhaler found at the scene of the accident to Laure, who agrees to examine it, but is suspicious of his sudden collaboration with the police. Things get a little more complicated for Richard, who learns that Leila has a sufficient alibi to prove Kevin's innocence. He becomes the confidant of the lawyer to stay as close as possible to the investigation, even if it means canceling the dinner with Laure at the last moment. Richard then persuades Laure and Behrami to grant Kevin immunity against his testimony. Kevin denounces Samir Belaid but, eaten away by guilt, decides to retract his testimony and tells Fred. Fred warns Richard in the nick of time. He tries to get the first plane out of there with his son. Lucas panics and runs away. Cornered, Richard calls Hélène, his mother-in-law, to tell her that it's over. Unable to bring herself to lose her grandson, she decides to call Simon Riva to tell him who actually ran over Mathieu – Kevin. Afterwards, Kevin and Leila leave the young man's family home to go and see Behrami, when Simon Riva's motorcycle appears and a man sitting behind him coldly shoots Kevin in the head.

Richard spends the night at Leila's so as not to leave her alone, as she is devastated by Kevin's death. He too is shaken by the turn of events. This brings Laure and Behrami to wonder whether there is a mole within the police force. Fred, disgusted by the situation, decides to cut off all contact with Richard but lets him know that Lucas is safe at his place. To exact revenge for Lebrun's death, Driss Abidi sends Samir Belaid to kill Bruno Riva in prison. Laure questions Simon Riva about Kevin's murder. After comforting Leila, Richard goes to Hélène's house to confront her about Kevin's murder; she confesses that she told Simon about Kevin. Meanwhile, Leila tells Laure about a car from the Pantin junkyard that could have cleared Kevin. Richard goes to pick up Lucas at Fred's house, but the teenager asks to go and live with his grandmother. When he's finally alone, Lucas goes to the hospital to visit Mathieu Riva. Simon finds him there and chases him. As he runs away, Lucas takes a puff of Ventolin. Laure continues her investigation and discovers that the car that could have exonerated Kevin has been burned. When she returns home, she finds Simon, who tells her about the visit of a young man with an inhaler. Surprised by this new development, she asks for a new analysis of the Ventolin found at the scene of the accident. Driss Abidi and Samir Belaid learn from Kevin's mother that he has received a large sum of money from Fred. Surprised, they decide to find him and make him talk. Bruno Riva is murdered in prison by a man sent by Samir. Analyses of the inhaler reveal that it was provided by Lucas's high school. Laure makes the most of her lunch with Richard to question him about the possible guilt of his son. He is upset by these allegations but still manages to make her question herself. Driss Abidi and his men find Fred and question him about his link with the case, but they are ambushed by the Rivas. Shooting breaks out and Fred, wounded, manages to escape. As he is about to be executed, Driss promises that he can find the man who tried to assassinate Mathieu: Rebecca gives him 48 hours. At the same time, Simon discovers that the vehicle involved in his brother's accident is in Hélène's name. He goes to her home and discreetly follows her to Lucas' high school. Simon recognizes the teenager; their eyes meet…

Simon chases Lucas into the high school, but Lucas manages to escape. Fred, seriously wounded, finds Karine, his pregnant wife, and begs her to accompany him to Richard's house. When Richard returns home, he discovers Fred covered in blood. Hélène, a retired nurse, manages to remove the bullet from the wound but fears that his condition will deteriorate. Laure questions Richard about his friendship with Fred: the judge remains vague. Suspicious, the commissioner then asks to question Lucas, but Richard says that he is at school. Meanwhile, Driss Abidi must find Fred. He takes advantage of Kevin's mother's friendship with Karine to get her phone number. Knowing Fred is wounded, Driss offers Karine his help, but she hangs up on him. Hélène understands the situation immediately. Richard takes advantage of his new affair with Leila to push her to consider that Laure could be the mole. To support his theory, he tricks Laure by sending her a package from "Simon R" so that he can photograph her alongside the mafia in a compromising position. Fred's condition worsens. Hélène calls Driss Abidi for help, promising to reveal who hit Mathieu if he helps Fred. Driss keeps his word and arrives at Richard's house with a doctor. Once Fred is stabilized, Driss takes him and Hélène with him. Simon returns to Lucas' high school. He recognizes Lou, and manages to manipulate her into showing him pictures of her and Lucas. Simon then understands that it is Lucas Altman, the son of the judge who sent his father to prison. Simon breaks into Altman's house and logs on to the judge's computer. He sends a text message to Lucas, pretending to be Richard, and meets him under the Alexander III bridge. Lucas falls into the trap. Under the bridge, Simon threatens Lucas with a gun and, surprisingly, questions him about the necklace he is wearing. Angry, Lucas answers that it belonged to his mother. Simon tears off the pendant before running away. Relieved and in tears, Lucas finds his father. Meanwhile, Laure has finally understood Richard's shenanigans. She tries to denounce him to Behrami, but Leila gets there first. Laure is dismissed from the case. Driss leads Hélène to Rebecca. Without any hesitation, she takes full responsibility for the accident. Rebecca asks Driss to execute Hélène to prove his loyalty, and sends Richard a picture of the corpse. The judge discovers the picture, horrified. He then notices two letters that Hélène had left for him and Lucas. In a heart-wrenching farewell, she says she has sacrificed herself because she loves them.

Laure breaks into Richard's apartment to find evidence for his lie. She explains her theory to Bastien, who reveals to her that it was Leila who anonymously received the incriminating photos of her and Simon. Rebecca is summoned for witness identification in the Mila Gomez affair. Seeing his mother helpless, Simon reassures her: they now have enough to blackmail Judge Altman because it was not Hélène who committed the hit-and-run but Lucas. Rebecca demands that Richard obtain the contact details of the witness, and does not hesitate to threaten Lucas. Cornered, Richard complies. Meanwhile, Laure visits Leila and shares her suspicions about Richard. Karine, still without news of Fred, seeks help from Richard. They learn that Fred is being held prisoner by Driss Abidi, and Richard manages to free him despite the danger. Grateful, Fred and Karine suggest taking Lucas with them to Portugal, where they intend to flee. Leila returns to the scrapyard to see the car that could have cleared Kevin, and realizes that Laure was telling the truth. She begins to believe her theory. Before leaving, Lucas goes to say goodbye to Gabrielle. But she rejects him, and advises him to take responsibility for his actions. Everything changes for Lucas: he goes to the police station and decides to confess. Richard is forced to silence the witness in the Mila Gomez case. Rebecca then offers to continue their alliance by protecting Lucas in prison in exchange for Richard's services as a future prosecutor. Richard retorts that Behrami will be nominated, but Rebecca insinuates that this could change without Behrami in the picture. Richard understands the threat and rushes to find his colleague. Too late! Riva's men shoot Behrami and Leila. Richard saves Leila, but Behrami dies. Leila is furious with Richard, but decides not to denounce him as he saved her life. Richard has lost everything. He receives a visit from Simon, who gives him back his wife's necklace, torn from Lucas' neck. Richard demands to know how he got hold of it, but Simon advises him to talk to his son. Out for revenge, Richard tells Simon the truth about his mother's role in his father's imprisonment. In prison, Richard questions Lucas about the necklace. He then reveals the unthinkable to him. Mathieu Riva raped his mother on the day of her suicide. Lucas did not confess anything to his father because he knew he was with his mistress that very day. It was on purpose, after recognizing Mathieu during his driving test, that Lucas knocked him down. A little later, Richard goes to the Rivas, armed. We hear a gunshot.