Following the death of Sami, Captain Laure Berthaud is trying to cope as best she can. But her personal life, already a mess, threatens to be derailed further when she receives some unexpected news. Working with her trusted team, she leads an investigation into a shocking double murder.

Laure's team manages to track down Stéphane Jaulin, whose lawyer turns out to be Pierre Clément. Clément takes to Jaulin's defence and clashes with Judge Roban, who sees his client as the perfect fit for the crime.

The double murder investigation steers Laure's team towards a group of bank raiders. Laure is not convinced of Jaulin's involvement, but Roban insists that the father has failed to tell the whole truth.

Laure tries to convince Roban that he is mistaken in his pursuit of Jaulin and decides to concentrate on tracking down the raiders, but new evidence emerges which proves damning for Jaulin.

Herville strives to endear himself to the police commissioner, who is eager to have a case resolved in order to whip up positive publicity, so Gilou steps in with a daring suggestion.

While pursuing the raiders, police come across new evidence which could potentially shift the focus of the double murder investigation.

Devastated by Pierre's death, Josephine struggles to keep herself together. Laure is also affected, and the two women find some common ground in their shared grief.

The operation to capture Zacharie Gabbai has failed and he is now on the run. The police decide to set him a trap. Laure looks into the period in which Sandrine Jaulin's parents worked as a foster family, and a troubling history emerges.

Gilou is taken into custody, as his team looks on in dismay. Herville clashes with his superiors. The identity of Lucie Jaulin's biological father is finally established. Egged on by Edelman, Joséphine defends Tarek Ziani and engages in a power struggle with Roban.

The investigation picks up when police find a fingerprint amongst Gabbai's belongings which links to the crime scene of the double murder. But who does the print belong to? Gilou is charged with conspiracy and, in an effort to get him off the hook, Laure goes out of her way to request help from the most unlikely of quarters.

Following the savage attack on Kimberley, the noose tightens around the criminal activities of Karen's girl gang. But as the police start to close in, they strike again. Meanwhile, it's time to find out whether Josephine's audacity has paid off in her defence of Gilou.

Roban can't stand to see Tarek Ziani elude his charges and tries to bring him down using the Crime Unit's investigation into a luxury vehicle racket. But Gilou's dealings with a prominent police informant threaten the outcome of the operation.