Vincent and Alban manage to escape their pursuers at the last minute, but Louise is kidnapped and all seems lost. Vincent rushes to try to save her as she is held captive in an abandoned airfield.

Vincent and Alban begin to grasp the magnitude of the conspiracy they have stumbled upon, but they don't have time to investigate. Victims of blackmail, they have no choice but to retrieve a music box by breaking into the home of Marat Milankovitch, an extremely dangerous Russian oligarch.

In a Moroccan prison, Vincent and Alban are threatened with death if they don't carry out a dangerous mission: find out where one of their fellow inmates, Attila, a bloodthirsty psychopath, has hidden a shipment of drugs. With Christmas approaching and their hearts set on returning home to their loved ones, the situation seems hopeless.

It's the final stretch for Vincent and Alban, who are determined to return home but are still carrying a dangerous vial. Vincent uses it as a bargaining chip to negotiate with the DGSE to get their old lives back. But in Beaucastel, in the middle of the Christmas market, all their enemies converge, ready to do anything to neutralize them once and for all.

On his way to work, Vincent, in his thirties, picks up a ringing cell phone from the ground and answers it. He hears a woman screaming and a threatening voice saying, “If you're not there by 5 p.m., we'll kill your wife.” Alban, his 45-year-old colleague with a fiery temperament, already sees himself as the hero of the day and urges Vincent to take action.

Following a misunderstanding, Vincent and Alban are mistaken for scientists who are experts in biological weapons and find themselves members of a mercenary commando unit searching for VX, a formidable biological weapon that they must steal from a high-security laboratory in Scotland.