“During a trip to America, it is learned that famous thief Arsène Lupin has made it aboard the ship. The ship’s guests, led by Bernard d’Andrèzy, try to weed out the thief with only a partial description of his appearance and the first letter of the alias he is using.”
“Baron Nathan Cahorn receives a letter from Arsène Lupin, who is incarcerated in La Santé Prison, wherein the thief tells Cahorn to send him several of his valuables or else he will come on 27 September to steal those named and more.”
“Having learned that Arsène Lupin plans to escape before his trial, the police allow it to happen while secretly watching him in order to arrest his accomplices.”