After several spectacular jewel thefts an international group of insurance underwriters plan to trap the culprits by following the buyer of the Karenina diamonds.Enter man of mystery,jewel dealer Ricardo Cortez who makes the purchase,leaves Paris on the Orient Express,and is followed by numerous people hoping to get their hands on the gems.The viewer must figure out just who is an actual thief/murderer or those who are on the side of the law in this delightfully fast-paced thriller.A trainload of wonderful Warner Brothers contract players(Mary Astor,Robert H.Barrat,John Wray,Irving Pichel,Dudley Digges,Ferdinand Gottschalk,etc.) and the always terrific direction of Robert Florey keep the suspense right on track.