Caplan, Morlighem, Vachewski and Roxane arrest Lemoine, a big time bandit, after extracting information from his attorney. But the man is released on a technicality. Meanwhile, their charismatic team leader, Rossi, is accused of rape. A complaint has been lodged by Benaissa, a man questioned by Rossi about a murder case. The police inspection services get involved. In an effort to clear their chief's name, the 4 cops set out to solve the murder case in which Benaissa is implicated. Their lives will never be the same again...

There's no time to breathe! It's a painful, soul-destroying period. Fortunately, the divisional chief superintendent, who is supportive towards them, is still around for a few days before he is due to retire. However, the group starts to crumble under the pressure. Roxane, for one, is struggling with his conscience. When Lemoine beats up Vachewski, he finds out that it was his attorney who gave him over to the cops. Morlighem has poker debts and he's asking Caplan to help him find a solution.

Their lives becomes dominated by lies and slipping through nets, anything to save their skins! Inspector general Vogel is going all-out to get Caplan and his friends, with the help of the prosecutor. They try to get them implicated in various shady cases currently under investigation. The four cops are fully aware of the constant risks they are taking, not only for themselves but for their families too. They make their ways through the booby-traps laid down for them, still leading their regular police investigations all the while. One of these investigations gives them a lead on a gang of ATM robbers.

Unable to reimburse his gambling debts, Morlighem is kidnapped by a gang of gypsies. The kidnappers send pictures of him being tortured along with a ransom note. If he's going to come up with the money and save him, Caplan has no other choice, he must call on Lemoine. The countdown has begun. The roughneck puts him on a job, an ATM bust, no less!

Caplan is up against the wall, he has agreed to stage an ATM hold-up with Lemoine, to get the money for Morlighem's ransom. But when he gets there, Lemoine is nowhere to be found and an unpleasant surprise awaits him. Caplan realises that the hoodlum has leaked the hold-up info to the cops, and is making the most of the subsequent diversion to go and rob a diamond merchant! Surrounded by the local detective agency, headed by Roxane, Caplan and Vachewski manage to escape from their colleagues' clutches just in the nick of time. Time is running out. And, if they have any hope at all of saving Morlighem, they must find Lemoine fast and retrieve the diamonds.

Time is ticking over and they still don't have Morlighem's ransom money, having been outwitted by Lemoine yet again! Caplan accepts Bordier's proposal, which consists of re-drafting veterans of the Reserve Investigation Unit. A top secret operation is launched, a last-ditch effort to free Morlighem. Meanwhile, Vachewski finds out that the crime squad is working on identifying the two ATM robbers using CCTV footage. The vice is tightening around them! This period of extreme tension brings the four cops closer together than ever. They now know the score: if one of them falters, they all go down.