Deep in my memories, I had not noticed our path, but now the dark forms of my guides paused beside a gap in the stone flagging, where a stairway which I had never seen during my wanderings about the castle led into subterranean depths. Down this stairway I was conducted, and presently I came to realize that there was light of a sort--a dim, phosphorescent radiance that came from no recognizable source, and seemed to be less actual light than the accustoming of my eyes to the near-darkness. I went down for a long time. The stairway turned and twisted in the rock, and the bobbing forms ahead were my only relief from the monotony of the interminable descent. And at last, deep underground, the long stairway ended, and I gazed over the shoulders of my guides at the great door that barred my path. It was roughly chiseled from the solid stone, and upon it were curious and strangely disquieting carvings, symbols which I did not recognize. It swung open, and I passed through and paused, staring about me through a gray sea of mist. I stood upon a gentle slope that fell away into the fog-hidden distance, from which came a pandemonium of muffled bellowing and high-pitched, shrill squeakings vaguely akin to obscene laughter. Dark, half-glimpsed shapes swam into sight through the haze and disappeared again, and great vague shadows swept overhead on silent wings. Almost beside me was a long rectangular table of stone, and at this table two score of men were seated, watching me from eyes that gleamed dully out of deep sockets. My two guides silently took their places among them. And suddenly the thick fog began to lift. It was swept raggedly away on the breath of a chill wind. The far dim reaches of the cavern were revealed as the mist swiftly dissipated, and I stood silent in the grip of a mighty fear, and, strangely, an equally potent, unaccountable thrill of delight. A part of my mind seemed to ask, "What horror is this?" And another part whispered, "You know this place!" But I could never have seen it before. If I had realized what lay far beneath the castle I could never have slept at night for the fear that would have obsessed me. For, standing silent with conflicting tides of horror and ecstasy racing through me, I saw the weird inhabitants of the underground world. Demons, monsters, unnamable things! Nightmare colossi strode bellowing through the murk, and amorphous gray things like giant slugs walked upright on stumpy legs. Creatures of shapeless soft pulp, beings with flame-shot eyes scattered over their misshapen bodies like fabled Argus, writhed and twisted there in the evil glow. Winged things that were not bats swooped and fluttered in the tenebrous air, whispering sibilantly--whispering in _human_ voices.