An elderly woman believes that a precious treasure holds the key to finding her missing brother, who was kidnapped by the Nazis during the Second World War, and Jean seeks Dom's help to reunite the siblings. Meanwhile, Madame Blanc continues to watch Jean from a distance.

Albert Gilbert is left unconscious by robbers when a rare painting is stolen from his home and Caron calls upon Jean for her expertise in the investigation of the theft. Meanwhile, at Charlie and Simone's pawn shop, a local man demands his money back on a fake painting.