Martin, leader of Group 45, is about to hand over the reins of his commando. However, Martin captures Zaïd, an important French emir of Daesh, who, in exchange for the exfiltration of his daughter and grandson, is prepared to collaborate with the French.

The day after the start of the Battle for Mosul, the commando team, accompanied by their new Iraqi interpreter, return to the sewers to try to locate Fares under the cover of a security mission while Olivier is in a coma.

Despite Salwa's unsuccessful exfiltration, thanks to information from the Kurds, Group 45 picks up the trail that will lead them straight into a trap. Meanwhile, Hilaire and Mélissa, Adèle's assistants, follow the trail of the humanitarian convoy.

In 2016, on the outskirts of Mosul, still in the hands of Daesh, a French special forces commando is in charge of capturing French fighters of the Islamic State. Sometimes they succeed, but sometimes the operation goes wrong.

As the commandos set off to attack a suspected hideout of Farès and Salwa, Adèle learns some terrible news.

Once the commando had returned to base, the whole task force is mobilised to find their missing operator. Zaïd offers his help under certain conditions.