Following the birth of Léo, Morgane and her four children moved in with Karadec, with whom she is now a co-parent and roommate, in addition to being a colleague! And after a parental leave consisting of sleepless nights and camping in the living room, it's back to work for our two heroes. But, between fatigue, the eternal custody problems and a mysterious crime that quickly turns into a nervous breakdown... This 24-hour day could well be the longest of their lives!

It's finally Léo's first day of daycare, and Morgane arrives at a crime scene where the victim was a carpooler when suddenly, she sees Karadec arrive... with their baby! But who brings their children to a crime scene, our consultant is offended! And yes, the commander is having trouble cutting the cord, much to the dismay of Morgane, who has seen it all. While untangling this story of cigarette poisoning, estranged cousins, and a dog shelter, our two heroes could well be troubled by their new relationship as co-parents.

A woman presents herself to the DIPJ to report an assault that hasn't yet taken place! A clairvoyant, she claims to communicate with spirits, only to be murdered herself! While Morgane and Karadec struggle to continue working as a team while hiding the new nature of their relationship, Daphné tries her hand at spiritualism, and what appears to be a hoax quickly turns into the hunt for a cold-blooded killer.

After receiving some unfortunate news about her father Serge, Morgane is forced to take the train with her family to Boulogne-sur-Mer. It's like the end of the world for our already overworked mother. On the train, which is nothing like the Orient Express, Morgane spots all sorts of strange clues that make her fear that one of the passengers has been kidnapped during their journey! Brilliant intuition or one too many delusions? While Morgane tries to escape her destiny and especially Karadec, he might well come knocking at her door again. For a new start?