All eight episodes from the fourth season of Olivier Marchal's French police thriller. The series follows a group of police officers led by Eddy Caplan (Jean-Hugues Anglade) who use violent and unorthodox methods in their criminal investigations. When this is brought to the attention of Internal Affairs, the department is faced with the difficult and dangerous task of exposing the group's methods and putting a stop to them. In this season, Caplan and his team are confronted by a ruthless criminal looking for revenge after his son is killed in a police raid. With the authorities watching them closely, the team once again risk it all to take down their target.