He did not see her. On tiptoe he glided across the hall and vanished through an open door. A moment later she heard a choking cry, and then silence fell again.

Consumed with curiosity, Valeria glided along the gallery until she came to a door above the one through which the man had passed. It opened into another, smaller gallery that encircled a large chamber.

This chamber was on the third floor, and its ceiling was not so high as that of the hall. It was lighted only by the fire-stones, and their weird green glow left the spaces under the balcony in shadows.

Valeria's eyes widened. The man she had seen was still in the chamber.

He lay face down on a dark crimson carpet in the middle of the room. His body was limp, his arms spread wide. His curved sword lay near him.

She wondered why he should lie there so motionless. Then her eyes narrowed as she stared down at the rug on which he lay. Beneath and about him the fabric showed a slightly different color, a deeper, brighter crimson.

Shivering slightly, she crouched down closer behind the balustrade, intently scanning the shadows under the overhanging gallery. They gave up no secret.

Suddenly another figure entered the grim drama. He was a man similar to the first, and he came in by a door opposite that which gave upon the hall.

His eyes glared at the sight of the man on the floor, and he spoke something in a staccato voice that sounded like "Chicmec!" The other did not move.

The man stepped quickly across the floor, bent, gripped the fallen man's shoulder and turned him over. A choking cry escaped him as the head fell back limply, disclosing a throat that had been severed from ear to ear.

The man let the corpse fall back upon the blood-stained carpet, and sprang to his feet, shaking like a windblown leaf. His face was an ashy mask of fear. But with one knee flexed for flight, he froze suddenly, became as immobile as an image, staring across the chamber with dilated eyes.

In the shadows beneath the balcony a ghostly light began to glow and grow, a light that was not part of the fire-stone gleam. Valeria felt her hair stir as she watched it; for, dimly visible in the throbbing radiance, there floated a human skull, and it was from this skull—human yet appallingly misshapen—that the spectral light seemed to emanate. It hung there like a disembodied head, conjured out of night and the shadows, growing more and more distinct; human, and yet not human as she knew humanity.

The man stood motionless, an embodiment of paralyzed horror, staring fixedly at the apparition. The thing moved out from the wall and a grotesque shadows moved with it. Slowly the shadow became visible as a man-like figure whose naked torso and limbs shone whitely, with the hue of bleached bones. The bare skull on its shoulders grinned eyelessly, in the midst of its unholy nimbus, and the man confronting it seemed unable to take his eyes from it. He stood still, his sword dangling from nerveless fingers, on his face the expression of a man bound by the spells of a mesmerist.

Valeria realized that it was not fear alone that paralyzed him. Some hellish quality of that throbbing glow had robbed him of his power to think and act. She herself, safely above the scene, felt the subtle impact of a nameless emanation that was a threat to sanity.

The horror swept toward its victim and he moved at last, but only to drop his sword and sink to his knees, covering his eyes with his hands. Dumbly he awaited the stroke of the blade that now gleamed in the apparition's hand as it reared above him like Death triumphant over mankind.

Valeria acted according to the first impulse of her wayward nature. With one tigerish movement she was over the balustrade and dropping to the floor behind the awful shape. It wheeled at the thud of her soft boots on the floor, but even as it turned, her keen blade lashed down and a fierce exultation swept her as she felt the edge cleave solid flesh and mortal bone.

The apparition cried out gurglingly and went down, severed through the shoulder, breastbone and spine, and as it fell the burning skull rolled clear, revealing a lank mop of black hair and a dark face twisted in the convulsions of death. Beneath the horrific masquerade there was a human being, a man similar to the one kneeling supinely on the floor.

The latter looked up at the sound of the blow and the cry, and now he glared in wild-eyes amazement at the whiteskinned woman who stood over the corpse with a dripping sword in her hand.

He staggered up, yammering as if the sight had almost unseated his reason. She was amazed to realize that she understood him. He was gibbering in the Stygian tongue, though in a dialect unfamiliar to her.

"Who are you? Whence come you? What do you in Xuchotl?" Then rushing on, without waiting for her to reply: "But you are a friend—goddess or devil, it makes no difference! You have slain the Burning Skull! It was but a man beneath it, after all! We deemed it a demon they conjured up out of the catacombs! Listen!"

He stopped short in his ravings and stiffened, straining his ears with painful intensity. The girl heard nothing.

"We must hasten!" he whispered. "They are west of the Great Hall! They may be all around us here! They may be creeping upon us even now!"

He seized her wrist in a convulsive grasp she found hard to break.

"Whom do you mean by 'they?'" she demanded.

He stared at her uncomprehendingly for an instant, as if he found her ignorance hard to understand.

"They?" he stammered vaguely. "Why—why, the people of Xotalanc! The clan of the man you slew. They who dwell by the eastern gate."

"You mean to say this city is inhabited?" she exclaimed.

"Aye! Aye!" He was writhing in the impatience of apprehension. "Come away! Come quick! We must return to Tecuhltli!"

"Where is that?" she demanded.

"The quarter by the western gate!" He had her wrist again and was pulling her toward the door through which he had first come. Great beads of perspiration dripped from his dark forehead, and his eyes blazed with terror.

"Wait a minute!" she growled, flinging off his hand. "Keep your hands off me, or I'll split your skull. What's all this about? Who are you? Where would you take me?"

He took a firm grip on himself, casting glances to all sides, and began speaking so fast his words tripped over each other.

"My name is Techotl. I am of Techultli. I and this man who lies with his throat cut came into the Halls of Silence to try and ambush some of the Xotalancas. But we became separated and I returned here to find him with his gullet slit. The Burning Skull did it, I know, just as he would have slain me had you not killed him. But perhaps he was not alone. Others may be stealing from Xotalanc! The gods themselves blench at the fate of those they take alive!"

At the thought he shook as with a ague and his dark skin grew ashy. Valeria frowned puzzledly at him. She sensed intelligence behind this rigmarole, but it was meaningless to her.

She turned toward the skull, which still glowed and pulsed on the floor, and was reaching a booted toe tentatively toward it, when the man who called himself Techotl sprang forward with a cry.

"Do not touch it! Do not even look at it! Madness and death lurk in it. The wizards of Xotalanc understand its secret—they found it in the catacombs, where lie the bones of terrible kings who ruled in Xuchotl in the black centuries of the past. To gaze upon it freezes the blood and withers the brain of a man who understands not its mystery. To touch it causes madness and destruction."

She scowled at him uncertainly. He was not a reassuring figure, with his lean, muscle-knotted frame, and snaky locks. In his eyes, behind the glow of terror, lurked a weird light she had never seen in the eyes of a man wholly sane. Yet he seemed sincere in his protestations.