We discover a macabre scene in front of the church of a small village. The body of the priest is found naked, crucified on an inverted cross. Pierre Niemans and Camille Delaunay investigate this murder, the staging of which recalls the death of a 3rd century martyr. In addition, the relics of the saint have disappeared from the parish of the neighboring town. In full investigation, Camille discovers a note from the killer in his jacket: "The first letter of the Father's name has been pronounced." It is then that a second crime occurs; other relics are again stolen.
