When John Mannering — alias the Baron — picked up the receiver he heard a frightened man at the end of the line. When he later opened his front door he found a superbly confidant and supremely beautiful woman standing there. She had been robbed of diamonds and she needed Mannering's help. Were the two linked? As the story unfolds it consumes Mannering's friends and enemies, and sees the Baron and his wife put in grave danger. As the tension increases and time ticks by, Mannering must use his wits to escape the trap by which he has been ensnared and in which he might ultimately perish.