Madeleine, an eight-year-old girl, is the sole survivor and therefore witness to the triple murder of her parents and her four-month-old baby brother. However, the traumatized girl is completely amnesiac and mute. The investigation is entrusted to Benoît Belgarde, a unique police commander and father of four children (with a fifth on the way), who is determined to find the culprit or culprits. To help Madeleine overcome the post-traumatic shock, he decides to enlist the help of Marie Kempf, a former child psychiatrist with unconventional methods. She agrees but imposes one condition: that he reopens the investigation into the death of Lila, her teenage daughter, who apparently committed suicide three years ago…