seven o'clock
There is a well-known French restaurant in the `` Tenderloin '' district which provides its patrons with small but elegantly appointed private dining-rooms . The restaurant occupies a corner house ; and , though its reputation is not strictly first-class in some respects , its cook is an artist , and its wine cellar as good as the best . It has two entrances , and the one on the side street is not well lighted at night . At half-past seven o'clock one evening Nick Carter was standing about fifty yards from this side door . The detective had shadowed a man to a house on the side street , and was waiting for him to come out . The case was a robbery of no great importance , but Nick had taken it to oblige a personal friend , who wished to have the business managed quietly . This affair would not be worth mentioning , except that it led Nick to one of the most peculiar and interesting criminal puzzles that he had ever come across in all his varied experience .