Widow Simone d'Argentières lives in Neuilly with her son Jean and her friend Hélène Castillon, whose brother Georges wants to marry Simone. Both the chauffeur Pistol and the servant Malar are in love with the maid Prunette. Georges makes a deal with businessman Paramine in the hope of ending his financial troubles while Albert D'Amentières proposes to his sister-in-law Simone who declines arguing that she does not wish to give Jean a step-father. Hélène overhears this and repeats it to Georges who says in front of the servants: "What a shame she has a son'. Little Jean leaves for a vacation with old father Pailloux at the country. Gypsies settle near by and their leader Luigi meets Paramine who is here under the assumed name of Simon and gives him money. The next day, little Jean disappears.

In the early morning of 1911, Mona Lisa is found to be stolen from the Louvre museum. Museum officials look for Nick Winter help to dissolve the Mystery of the Century.

A motherless child has a tumultuous existence, but she eventually becomes a famous international opera singer. Past and present meet when she performs in her original home town.

Another fast-paced crime/detective short featuring the tough Nick Winter .