Maigret is notified through Interpol that Peter the Lett, an international fraudster and leader of the notorious Baltic Gang, is travelling to Paris. Furnished only with a description he and a squad from the Police Judiciaire plan to intercept him at the Gare du Nord. However, after seeing a man who matches the description Maigret is called to a carriage of the train to find a body, also matching the description he has.
