This series is loosely inspired by the Dupont de Ligonnès case, the unresolved 2011 murders of several members of the Dupont de Ligonnès family in Nantes. One family member, Xavier Dupont de Ligonnès, who is not among the victims and remains missing, is suspected of the murders.
Combining reality and fiction, the series begins with Christophe de Salin hitting Anna-Rose Gagnières, a cybersecurity specialist, one evening. A few weeks later, she learns that the Salin family has been found buried and that only the father, Christophe, is missing. Driven by this discovery, she embarks on a search for him, creating a Facebook group to aid her investigation. Simultaneously, the series delves into real details of Xavier Dupont de Ligonnès’s escape and imagines his life thereafter.