October 16th 1984. The body of Gregory Villemin, aged 4, is found drowned near a village in France. As dozens of reporters flock, the police follow the trail of a mysterious letter-writer.
A suspect is arrested, under the eyes of crazed journalists. This arrest highlights existing family conflicts. Meanwhile, the police question the suspect's sister-in-law.
While the police believe they hold the culprit of the murder in the person of Bernard Laroche, their key witness recedes her statement. But an unexpected testimony brings out a new theory.
Sesmat is replaced as lead investigator with Corazzi, who firmly believes Christine is guilty. Feeling abandoned by everyone, Jean-Marie considers taking justice into his own hands.
The noose tightens around Christine, while Jean-Marie must face the consequences of his act. The case gets even more publicized when a famous writer publishes an article about it.
Christine goes on a hunger strike to protest against her arrest. She then publishes a book to defend herself. Meanwhile, Lambert uses his last resources to try and finally solve the case.