Conan turned and peered into the darkness, an icy finger crawling along his spine. Then he went along the corridor, cat-footed, and without hesitation, moving deeper and deeper into the darkness as he drew farther away from the stair. The air hung heavy with the odor he had scented in the court of the gong. Now in utter blackness he heard a sound ahead of him--the shuffle of bare feet, or the swish of loose garments against stone, he could not tell which. But an instant later his outstretched hand encountered a barrier which he identified as a massive door of carven metal. He pushed against it fruitlessly, and his sword-point sought vainly for a crack. It fitted into the sill and jambs as if molded there. He exerted all his strength, his feet straining against the door, the veins knotting in his temples. It was useless; a charge of elephants would scarcely have shaken that titanic portal. As he leaned there he caught a sound on the other side that his ears instantly identified--it was the creak of rusty iron, like a lever scraping in its slot. Instinctively action followed recognition so spontaneously that sound, impulse and action were practically simultaneous. And as his prodigious bound carried him backward, there was the rush of a great bulk from above, and a thunderous crash filled the tunnel with deafening vibrations. Bits of flying splinters struck him--a huge block of stone, he knew from the sound, dropped on the spot he had just quitted. An instant's slower thought or action and it would have crushed him like an ant. Conan fell back. Somewhere on the other side of that metal door Muriela was a captive, if she still lived. But he could not pass that door, and if he remained in the tunnel another block might fall, and he might not be so lucky. It would do the girl no good for him to be crushed into a purple pulp. He could not continue his search in that direction. He must get above ground and look for some other avenue of approach. He turned and hurried toward the stair, sighing as he emerged into comparative radiance. And as he set foot on the first step, the light was blotted out, and above him the marble door rushed shut with a resounding reverberation. Something like panic seized the Cimmerian then, trapped in that black tunnel, and he wheeled on the stair, lifting his sword and glaring murderously into the darkness behind him, expecting a rush of ghoulish assailants. But there was no sound or movement down the tunnel. Did the men beyond the door--if they were men--believe that he had been disposed of by the fall of the stone from the roof, which had undoubtedly been released by some sort of machinery? Then why had the door been shut above him? Abandoning speculation, Conan groped his way up the steps, his skin crawling in anticipation of a knife in his back at every stride, yearning to drown his semi-panic in a barbarous burst of blood-letting.