A few minutes later I walked into the store beneath Big Sam’s residence and put foot on the dingy stair that led to his office. A short, stout Chinaman tried to halt me with a "What you wan’?" but I pushed him aside and passed up the steps. I knew my way through the semi-darkness of the passage, and stumbled upward without wish for guidance or thought of danger. I had not mounted half the ascent before I heard something of a commotion above me--the shutting of a door, a scurry of feet, and a rumbling sound as though a heavy table had been moved across the floor. I amused myself with the thought that I had caught Big Sam’s household unprepared for visitors and imagined the flight of the feminine portion of his family at the sound of my approaching footfall. I reached the landing. The hall was deserted, and, turning toward the building’s front, I knocked at the one door that led from the passage. There was no answer, and I knocked again. As a third knock brought no response I turned the knob and opened the door for myself. To my surprise Big Sam’s room of state had disappeared. In place of the large and handsome office, with its profusion of ornamentation and its oriental furniture, I found myself looking into a narrow passageway between blank walls. I looked about the hall with the thought that I must have mistaken the door. But there was no other entrance to be seen, and I looked again in perplexity at the passage, unwilling to believe the evidence of my eyes. As I turned to make sure of the transformation I heard a click as of a spring lock snapped, a smart push at my back sent me staggering forward, and the door banged behind me. It took but a moment to recover myself and face about. But I was too late. The door had been securely locked. A few blows on the panels sufficed to assure me that it was of too solid construction to yield to anything less powerful than an ax; and though the frame rattled at my efforts, I saw that I was a prisoner, unless I could find some other way of egress. I spared the door the kicks and blows that were called for by my first impulse. If I had been fool enough to get into this trap, I had at least sense enough to recognize that I should not better myself by knocking the skin off my knuckles in the effort to attract attention. The persons whose ears I could reach did not need to be informed of my presence. They had attended to the little detail of putting me there, and might be assumed to be aware of the honor I was doing them without further demonstration of the fact. I turned to look once more at my prison. It was hardly five feet wide, and might have been thirty feet long, and appeared to turn a sharp corner and lead toward the rear of the building. Evidently I was at the entrance of one of the labyrinths of Chinatown, famous in police reports.