Jean-Baptiste Adamsberg, the commissioner of the Paris criminal investigation division, has a younger brother—Rafael—accused of murdering a friend, acquitted by the court, but not by public opinion, and who disappeared in an unknown direction—for thirty years. From the very beginning, Commissioner Adamsberg knew that the real murderer was Judge Foulzhans, but no matter how hard he tried, he couldn’t prove anything. In the end, he receives the news that the judge has died. And many years later, a murder occurs in which Adamsberg recognizes the handwriting of Foulzhans.