On 16 October 1984, the four-year-old Grégory Villemin disappeared. A few hours later, he was found dead in the Vologne, bound hand and foot, with his cap covering his face.

New evidence allows judge Lambert to identify a potential suspect in the death of Grégory. The arrest causes trouble within the Villemin family.

While the gendarmes believe they have the culprit for Grégory's death in the person of Bernard Laroche, their witness goes back on his confession.

The investigation is assigned to the regional police of Nancy, lead by commissioner Corazzi who believes that the child's mother is guilty.

The noose is tightening around Christine Villemin while her husband, Jean-Marie, must face the consequences of his act.

Christine Villemin, imprisoned, starts a hunger strike to protest, quickly followed by her husband. Under pressure, Judge Lambert plays his last cards to try to shed light on this extraordinary case.