This Night's Foul Work

On the outskirts of Paris, two men have been found murdered. It is assumed that this is a drug-related incident, but Commissaire Adamsberg is not convinced. The trail also leads Adamsberg to a cemetery, where a grave has been disturbed with no apparent motive.Could this be the work of a serial killer caught by Adamsberg two years ago and recently escaped from prison? Meanwhile a new lieutenant has been assigned to the team. There is something disquieting about him, not least when it emerges that he is from a neighbouring village in the Pyrenees, known for its feuds with Adamsberg's own childhood home.