I was half-way up the stairway when something undefined brought me to a sudden stop. Some nocturnal adeptness of instinct warned me of an imminent presence, of a menace that had not yet disclosed itself.
Once more I came to a stop, straining my eyes through the darkness. Nothing whatever was to be seen. Along the floor of the hallway just above my head, however, passed a small but unmistakable sound. It was the soft frou-frou of a skirt, a skirt of silk or satin, faintly rustling as a woman walked the full length of the hall. I had just made a mental register of the deduction that this woman was dressed in street-clothes, and was, accordingly, an intruder from outside, rather than a sleeper suddenly awakened, when a vague suffusion of light filled the space above me and was as quickly quenched again.
I knew the moment I heard the soft thud of wood closing against wood, that a door had been quietly opened and as quietly closed again. The room into which that door led must have been faintly lighted, for it was the flowering of this refracted light that had caught my attention.
I went silently up the stairs, step by step, listening every now and then as I advanced. Once I reached the floor level I kept close to the wall, feeling my way along until I came to the door I wanted.
There was no way whatever of determining what stood on the other side of that door, without opening it. I knew what risks I ran in attempting any such movement. But I decided it was worth the risk.
Now, if a door is opened slowly, if every quarter-inch of movement is measured and guarded, it can, as a rule, be done noiselessly. I felt quite sure there was not one distinguishable sound as I cautiously turned that bronze knob and even more cautiously worked back the door, inch by inch.
I came to a stop when it stood a little more than a foot from the jamb. I did not, at first, attempt to sidle in through the aperture; that would have been needlessly reckless. I stood there waiting, anticipating the effect the door-movement might have had on any occupant of the room, had it been seen.
While I waited I also studied that portion of the chamber which fell within my line of vision. I saw enough to convince me that the room was a bedroom. I could also make out that it was large, and from the rose-pink of its walls to the ivory-white of its furnishings it stood distinctly feminine in its note.
There was, I felt, a natural limit to that period of experimental inaction. The silence lengthened. The crisis of tedium approached, arrived, and passed. Audaciousness reconquered me, and I actually advanced a little into the room. Steadying myself with one hand on the door-frame, I thrust my body through the narrow aperture until the whole four walls lay subject to my line of vision.
The first thing I noticed was a green-shaded electric lamp burning on what seemed to be a boudoir writing-table. It left the rest of the room in little more than twilight. But after the utter darkness through which I had groped, this faint illumination was quite adequate for my purposes.