Trouble in Tangier... There was Paula, a lively, lovable English blond... and Bill, her adoring husband, intelligent, tough, and an expert pistol shot. There was Maureen, a fiery American Brunette... and Commandant Alvarez, a handsome Spaniard whose sense of honor was only exceeded by his courage. And of course there was the incomparable Sir Henry Merrivale, who had promised to solve another "impossible" case in forty-eight hours. And somewhere in Tangier was the mysterious Iron Chest... and the fabulous thief who went with it... the thief who had never been seen, and who was about to walk into the trap they had set for him, and walk out again, still unseen...!