When examining Maurice Lauzon's caravan, Jonas and P. Pineau discover two caliber 22 bullets and traces of blood. Maurice has not just disappeared, he may be dead. Constance learns that Serge saw the Orsini brothers near the naturist campsite on the evening of the disappearance. Police identify Stéphano Cozzolino's murderer using DNA found at the crime scene.

After their last visit to the naturist campsite, several strange tracks lead Constance and Jonas to suspect Paulo and Francine for the death of Maurice Lauzon. Is it the stolen objects or Maurice's body which is at the bottom of the lake? In the meantime, the squad is about to arrest Eddy Bazin.

The search organized by Sylvain to find his father is postponed due to the absence of the dog handler. Constance and Jonas take the opportunity to question Paulo and Francine. They are now serious suspects for the murder of Maurice Lauzon, but Fred and Antoine doubt it. A double murder occurs in Sainte-Thérèse.