The Parisian police and lawyers return for a fourth series of the acclaimed and riveting crime drama. Police Captain Laure Berthaud and her lieutenants, Gilou and Tintin, investigate when a student is abandoned by his accomplices in a forest near Paris after being blown asunder by their homemade bomb. Lawyer Joséphine Karlsson is getting herself into dangerous waters defending undocumented immigrants; her colleague, Pierre Clément, surprisingly finds himself representing crime boss, Johnny Jorkal; while Judge Roban returns to the Palais De Justice, sidelined and on the warpath. As the story unfolds to reveal a group of extremists intent on waging a war against the Parisian Gendarmerie and a dangerous arms-trafficking operation, the police and the lawyers begin to turn on each other in another tense and gripping series.