In November 2011 Agnès Marin, 13, vanishes from her boarding school in the Cévennes. Lieutenant-Colonel Depierre heads the enquiry. After 48 hours of interrogating witnesses and searching in wintery conditions, the body is found in the forest.

In 2002, the biggest case of pedophilia in France breaks out in Angers. For more than two years, Fabienne Lopéo of the juvenile brigade leads the investigation. It's a case that will affect his life deeply.

The murder of 16-year-old schoolgirl Christelle Maillery, committed at Le Creusot in 1986, is now resolved... 30 years after her death. The fact that the culprit is now under lock and key owes much to the obstinacy and the intelligence of one man, Raphaël Nedilko.

Eric Trunel, then commander at the legendary 36 Quai des Orfèvres, plunges ten years into the past to revisit a case that marked him. That of Susanna Zetterberg, a 19-year-old Swedish girl abducted as she left a Parisian nightclub, whose lifeless body was found in the Forest of Chantilly.

Valérie Bouvard, 42, is a police captain. For more than 15 years she has worked at the heart of Seine Saint Denis, the most criminogenic département in France. We find her on a criminal case she solved, the murder of Mamadou Magassouba, teacher and former boxing champion from Saint Ouen.

The night of April 7 2012, Maeva Rousseau, a young mother of 23, is found at home. The crime scene shows traces violence. Lieutenant Guillaume Bocrie has only recently taken command of the Research Unit group. It isn't his first crime scene, yet six years later it will continue to haunt him.