'It’s May 1910 and 17 year old Linda Duke has just received a strange message: a playing card, the Jack of Spades, in an envelope that was sent from Paris, where her widowed father, Professor Charles Duke, a noted but impractical Shakespearean scholar, has gone on a research trip. In the code devised by her late French mother Madeleine, who was a dedicated card-player, ‘Jack of Spades’ means treachery and danger. Her father knows that. But it is not his handwriting on the envelope. Linda is convinced he is in great danger, and being both brave and determined, decides to set out immediately to Paris to look for him, starting with the place where he was meant to be staying, a guest-house in the Latin Quarter called the Villa Ardennes.' (Source : http://writerunboxed.com/2009/07/22/more-good-news/#more-1336 )