An online clue leads the team to the anarchists' squat, but during a raid Thomas Riffaut manages to escape. A plastic bag found at the scene of Cetin's execution provides a vital DNA clue.

Kolabi is taken into custody and confronted with the evidence against him for the murder of Cetin. His sim card reveals further clues linking him to Rodi Ozbek and arms dealing.

Events reach a dramatic conclusion as the net draws in around Thomas Riffaut and his gang, but departmental in-fighting within the police organisation means that very dangerous loose ends remain on the streets of Paris.

A young couple has been spotted carrying the body of a mutilated man into the woods. Captain Laure Berthaud and her team soon discover that the unidentified man has been killed by a home-made bomb. The team is distracted by from their investigation by internal conflict and the appointment of a new commissioner who wants quick results.

Laure and her team are on the trail of Sophie Mazerat, a student whose car has been traced to the dumping of the bomb-damaged body, and arrest her at the university. Karlsson's attempts to have Moussa Kone freed from detention are hindered when Thomas's cell arranges a vicious reprisal attack against the bank which reported him.

Berthaud and her team stake out the Turkish restaurant that the Kurdish suicide victim was known to frequent, and uncover what appears to be an organised work crew of illegal immigrants.

The autopsy of the Kurd reveals a hidden clue which leads Herville to upgrade the case to the highest priority. Karlsson receives a visit from Special Branch, who attempt to blackmail her into providing information about Thomas Riffaut.

At a top-level police meeting called when a youth is shot dead in a drive-by killing, Herville boasts that his unit is already investigating a gun-running case and will have arrests within 24 hours. Karlsson visits Riffaut's new hideout and overhears the gang planning a kidnapping.

Berthault and her team are frustrated by new custody laws which ensure the presence of a lawyer during interviews. Gilou is given three days to ensure that the Sarahoui's late licence is approved and Roban is warned that Garnier is using underhand tactics to smear him.

When the police raid the Sarahoui's flat, Gilou takes the opportunity to break into their nightclub and retrieve incriminating evidence against him.

On learning of Cetin's release from police custody, the Ozbeks suspect him of informing against them and Rodi is ordered to eliminate him, but Rodi's associates have other ideas. Karlsson is called to the police station to answer a traffic offence, but is instead charged with perverting the course of justice.