A tall young man sped swiftly up the wide stone steps leading to the doorway of a mansion in one of Chicago's most fashionable avenues. After pushing the button sharply he jerked out his watch and guessed at the time by the dull red light from the panel in the door. Then he hastily brushed from the sleeve of his coat the telltale billiard chalk, whose presence reminded him that a general survey might be a wise precaution. He was rubbing a white streak from his trousers' leg when the door flew open and the butler admitted him to the hallway.