The Commissioner of the Parisian Criminal Investigation Department, Jean-Baptiste Adamsberg, has a younger brother - Raphael, accused of murdering his girlfriend, acquitted by the court, but not by public opinion, and disappeared in an unknown direction - for thirty years. Commissioner Adamsberg knew from the very beginning that the real murderer was Judge Fulgence, but no matter how hard he tried, he could not prove anything. Eventually news reaches him that the judge has died. And many years later, a murder occurs, in which Adamsberg recognizes Fulgence's handwriting.