Murilo realized that the priest must be centuries ahead of his generation, to perfect such an invention; but Conan put it down to witchcraft and troubled his head no more about it.
"I constructed these pits for a place of refuge as well as a dungeon," the priest was saying. "There are times when I have taken refuge here and, through these mirrors, watched doom fall upon those who sought me with ill intent."
"But why is Thak watching that door?" demanded Murilo.
"He must have heard the falling of the grating in the tunnel. It is connected with bells in the chambers above. He knows someone is in the pits, and he is waiting for him to come up the stairs. Oh, he has learned well the lessons I taught him. He has seen what happened to men who come through that door, when I tugged at the rope that hangs on yonder wall, and he waits to mimic me."
"And while he waits, what are we to do?" demanded Murilo.
"There is naught we can do, except watch him. As long as he is in that chamber, we dare not ascend the stairs. He has the strength of a true gorilla and could easily tear us all to pieces. But he does not need to exert his muscles; if we open that door he has but to tug that rope, and blast us into eternity."
"How?"
"I bargained to help you escape," answered the priest; "not to betray my secrets."
Murilo started to reply, then stiffened suddenly. A stealthy hand had parted the curtains of one of the doorways. Between them appeared a dark face whose glittering eyes fixed menacingly on the squat form in the scarlet robe.
"Petreus!" hissed Nabonidus. "Mitra, what a gathering of vultures this night is!"
The face remained framed between the parted curtains. Over the intruder's shoulder other faces peered—dark, thin faces, alight with sinister eagerness.
"What do they here?" muttered Murilo, unconsciously lowering his voice, although he knew they could not hear him.
"Why, what would Petreus and his ardent young nationalists be doing in the house of the Red Priest?" laughed Nabonidus. "Look how eagerly they glare at the figure they think is their arch-enemy. They have fallen into your error; it should be amusing to watch their expressions when they are disillusioned."
Murilo did not reply. The whole affair had a distinctly unreal atmosphere. He felt as if he were watching the play of puppets, or as a disembodied ghost himself, impersonally viewing the actions of the living, his presence unseen and unsuspected.
He saw Petreus put his finger warningly to his lips, and nod to his fellow conspirators. The young nobleman could not tell if Thak was aware of the intruders. The ape-man's position had not changed, as he sat with his back toward the door through which the men were gliding.
"They had the same idea you had," Nabonidus was muttering at his ear. "Only their reasons were patriotic rather than selfish. Easy to gain access to my house, now that the dog is dead. Oh, what a chance to rid myself of their menace once and for all! If I were sitting where Thak sits—a leap to the wall—a tug on that rope—"
Petreus had placed one foot lightly over the threshold of the chamber; his fellows were at his heels, their daggers glinting dully. Suddenly Thak rose and wheeled toward him. The unexpected horror of his appearance, where they had thought to behold the hated but familiar countenance of Nabonidus, wrought havoc with their nerves, as the same spectacle had wrought upon Murilo. With a shriek Petreus recoiled, carrying his companions backward with him. They stumbled and floundered over each other; and in that instant Thak, covering the distance in one prodigious, grotesque leap, caught and jerked powerfully at a thick velvet rope which hung near the doorway.
Instantly the curtains whipped back on either hand, leaving the door clear, and down across it something flashed with a peculiar silvery blur.
"He remembered!" Nabonidus was exulting. "The beast is half a man! He had seen the doom performed, and he remembered! Watch, now! Watch! Watch!"
Murilo saw that it was a panel of heavy glass that had fallen across the doorway. Through it he saw the pallid faces of the conspirators. Petreus, throwing out his hands as if to ward off a charge from Thak, encountered the transparent barrier, and from his gestures, said something to his companions. Now that the curtains were drawn back, the men in the pits could see all that took place in the chamber that contained the nationalists. Completely unnerved, these ran across the chamber toward the door by which they had apparently entered, only to halt suddenly, as if stopped by an invisible wall.
"The jerk of the rope sealed that chamber," laughed Nabonidus. "It is simple; the glass panels work in grooves in the doorways. Jerking the rope trips the spring that holds them. They slide down and lock in place, and can only be worked from outside. The glass is unbreakable; a man with a mallet could not shatter it. Ah!"
The trapped men were in a hysteria of fright; they ran wildly from one door to another, beating vainly at the crystal walls, shaking their fists wildly at the implacable black shape which squatted outside. Then one threw back his head, glared upward, and began to scream, to judge from the working of his lips, while he pointed toward the ceiling.
"The fall of the panels released the clouds of doom," said the Red Priest with a wild laugh. "The dust of the gray lotus, from the Swamps of the Dead, beyond the land of Khitai."
In the middle of the ceiling hung a cluster of gold buds; these had opened like the petals of a great carven rose, and from them billowed a gray mist that swiftly filled the chamber. Instantly the scene changed from one of hysteria to one of madness and horror. The trapped men began to stagger; they ran in drunken circles. Froth dripped from their lips, which twisted as in awful laughter. Raging, they fell upon one another with daggers and teeth, slashing, tearing, slaying in a holocaust of madness. Murilo turned sick as he watched and was glad that he could not hear the screams and howls with which that doomed chamber must be ringing. Like pictures thrown on a screen, it was silent.
Outside the chamber of horror Thak was leaping up and down in brutish glee, tossing his long hairy arms on high. At Murilo's shoulder Nabonidus was laughing like a fiend.
"Ah, a good stroke, Petreus! That fairly disemboweled him! Now one for you, my patriotic friend! So! They are all down, and the living tear the flesh of the dead with their slavering teeth."
Murilo shuddered. Behind him the Cimmerian swore softly in his uncouth tongue. Only death was to be seen in the chamber of the gray mist; torn, gashed, and mangled, the conspirators lay in a red heap, gaping mouths and blood-dabbled faces staring blankly upward through the slowly swirling eddies of gray.
Thak, stooping like a giant gnome, approached the wall where the rope hung, and gave it a peculiar sidewise pull.
"He is opening the farther door," said Nabonidus. "By Mitra, he is more of a human than even I had guessed! See, the mist swirls out of the chamber and is dissipated. He waits, to be safe. Now he raises the other panel. He is cautious—he knows the doom of the gray lotus, which brings madness and death. By Mitra!"
Murilo jerked about at the electric quality of the exclamation.
"Our one chance!" exclaimed Nabonidus. "If he leaves the chamber above for a few minutes, we will risk a dash up those stairs."
Suddenly tense, they watched the monster waddle through the doorway and vanish. With the lifting of the glass panel, the curtains had fallen again, hiding the chamber of death.
"We must chance it!" gasped Nabonidus, and Murilo saw perspiration break out on his face. "Perhaps he will be disposing of the bodies as he has seen me do. Quick! Follow me up those stairs!"
He ran toward the steps and up them with an agility that amazed Murilo. The young nobleman and the barbarian were close at his heels, and they heard his gusty sigh of relief as he threw open the door at the top of the stairs. They burst into the broad chamber they had seen mirrored below. Thak was nowhere to be seen.
"He's in that chamber with the corpses!" exclaimed Murilo. "Why not trap him there as he trapped them?"
"No, no!"