There is a well-known French restaurant in the "Tenderloin" districtwhich provides its patrons with small but elegantly appointed privatedining-rooms.
The restaurant occupies a corner house; and, though its reputation isnot strictly first-class in some respects, its cook is an artist, andits wine cellar as good as the best.
It has two entrances, and the one on the side street is not well lightedat night.
At half-past seven o'clock one evening Nick Carter was standing aboutfifty yards from this side door.
The detective had shadowed a man to a house on the side street, and waswaiting for him to come out.
The case was a robbery of no great importance, but Nick had taken it tooblige a personal friend, who wished to have the business managedquietly. This affair would not be worth mentioning, except that it ledNick to one of the most peculiar and interesting criminal puzzles thathe had ever come across in all his varied experience.
While Nick waited for his man he saw a closed carriage stop before theside door of the restaurant.
Almost immediately a waiter, bare-headed and wearing his white apron,came hurriedly out of the side door and got into the carriage, whichinstantly moved away at a rapid rate.
This incident struck Nick as being very peculiar. The waiter had actedlike a man who was running away.
As he crossed the sidewalk he glanced hastily from side to side, as ifafraid of being seen, and perhaps stopped.
It looked as if the waiter might have robbed one of the restaurant'spatrons, or possibly its proprietor. If Nick had had no business on hishands he would have followed that carriage.
As it happened, however, the man for whom the detective was watchingappeared at that moment.
Nick was obliged to follow him, but he knew that he would not have to gofar, for Chick was waiting on Sixth avenue, and it was in that directionthat the thief turned.
So it happened that within ten minutes Nick was able to turn this caseover to his famous assistant, and return to clear up the mystery of thequeer incident which he had chanced to observe.
Nick would not have been surprised to find the restaurant in an uproar,but it was as quiet as usual. He entered by the side door, ascended aflight of stairs, and came to a sort of office with a desk and aregister.
It was the custom of the place that guests should put down their namesas in a hotel before being assigned to a private dining-room.
There was nobody in sight.
The hall led toward the front of the building, and there were threerooms on the side of it toward the street.
All the doors were open and the rooms were empty. Nick glanced intothese rooms, and then turned toward the desk. As he did so he saw awaiter coming down the stairs from the floor above.
This man