In the wake of the Vernet murders in Aix-en-Provence, magistrate Bernard Martin moves to the town of Nancy in Lorraine, France, along with his pregnant wife Clarie, who is as fervent about Republican ideals as her husband. They are not in Nancy long when an infant boy is found dead, his tiny body mutilated. The wet nurse and mother say that this was a case of "ritual sacrifice" by a "wandering tinker," or Jew.

Yet as Bernard delves deeper into the different personalities surrounding the case, he struggles to reconcile his Republican beliefs with the subtle nuances of Nancy's Jewish Diaspora, all while balancing the racial tensions and politics within the courthouse. Meanwhile his beloved Clarie, now reeling from the death of her own child, seems to be falling prey to the propaganda being spewed throughout town, forcing Bernard to acknowledge the frailties of the human psyche. Fearing a vigilante mob sparked by the church, Bernard must unveil the murderers before Nancy experiences her own pogrom.