“This tunnel,” said Agvur, “runs upward to the exit near your vessel; and it leads down to the heart of our underworld realms. If the worst happens—as I fear it may—you will see only the antechambers of our labyrinth of caverns, in which we have dwelt, immune to disease and old age, for so many centuries. I am sorry; for I had hoped to take you to my own laboratories, in the nether levels. There you might have served me…in certain biologic tests.
“Ounavodo,” he went on, in calm explanatory tones, “has ordered the fusing and casting of a certain quantity of the mouffa-alloy, to be used in the making of new garments. This alloy, invented aeons ago by our metallurgists, is a compound of no less than six elements, and is made in two grades, one for the lining of our caverns, and the other exclusively for raiment.
“Both, for their perfection, require a seventh ingredient—a small admixture of living, protoplasmic matter, added to the molten metal in the furnace. Only thus—for a reason that is still mysterious to our savants—can the mouffa acquire its full power of insulation against the deadly solar rays.
“The mouffa used in comparatively heavy sheets for cavern-lining needs only the substance of inferior life-forms, such as the grokos, the half-animal savages of the twilight zone, and various creatures which we catch or breed in our underworld tunnels. But the higher grade of mouffa, employed in light, flexible sheets for suiting, requires the protoplasm of superior life.
“Regretfully, at long intervals, we have been compelled to sacrifice one of our own scanty number in the making of new metal to replace that which has become outworn. Whenever possible, we select those who in some manner have offended against our laws; but such infringements are rare, and commonly the victim has been chosen by a sort of divination.
“After studying you closely in his televisic mirror, Ounavodo has decided that you are sufficiently high in the evolutionary scale to provide the protoplasmic element in the next lot of mouffa. At least, he thinks that the test is worth trying, in the interests of science.”
“However, in order that you should not feel that you are being discriminated against or treated unjustly, you will merely take your chance of being chosen from among many others. The method of selection will be revealed to you in due time.”
While Agvur was speaking, the vehicle had sped swiftly down the endless incline, passing several other barge-shaped cars driven by the white, naked Immortals, whose serpentine locks flowed behind them on the air. Occasionally there were openings in the tunnel wall, leading no doubt to side-caverns; and after a mile or two, they came to a triple branching, where caverns ran upward at reverse angles from the main passage. Horrified and shaken as he was by Agvur’s disclosure, Howard took careful note of the route they were following.
He made no reply to the Mercutian. He felt his helplessness in the hands of an alien, extra-human race, equipped, it would seem, with scientific knowledge and power to which humanity had not yet attained. Thinking with desperate quickness, he decided that it would be better to pretend resignation to the will of his captors. His hand stole instinctively to the pocket in which he had carried the little tonanite pistol with its twelve charges of deadly heat-producing explosive; and he was dismayed, though hardly surprised, to find that the weapon was gone.
His movement was noted by Agvur; and a strange sardonic smile flickered across the unhumanly intellectual face of the savant. In his desperation, Howard thought of leaping from the car; but to do this would have meant death or serious injury at the high speed of their descent.
He became aware that the incline had ended in a large level cavern with numerous side-openings where multitudes of Oumnis were passing in and out. Here they left the boat-like vehicle; and Howard was led by Agvur through one of the side-exits, into another vast chamber, where perhaps fifty of the white people were standing in silent, semi-circular rows.
These beings were all fronting toward the opposite wall; but many of them turned to watch the earth-man with expressions of unreadable curiosity or disdain, as Agvur drew him forward to the first of the waiting ranks and motioned him to take his place at the end.
Now, for the first time, Howard saw the singular object which the Oumnis were facing. Apparently it was some sort of rootless plant-growth, with a swollen, yellowish bole or body like that of a barrel-cactus. From this body, tall as a man, leafless branches of vivid arsenic green, fringed with a white hispidity, trailed in limp, sinuous masses on the cavern-floor.
Agvur spoke in a piercing whisper: “The plant is called the Roccalim, and we employ it to choose, from a given quota, the person who shall be cast into the furnace of molten mouffa. You will perceive that, including yourself, there are about fifty candidates for this honor—all of whom, for one reason or another, in varying degrees, have incurred the displeasure of Ounavodo, or have given rise to doubt regarding their social usefulness. One by one, you are to walk about the Roccalim in a complete circle, approaching well within reach of the sensitive, mobile branches; and the plant will indicate the destined victim by touching him with the tips of these branches.”
Howard felt, as Agvur spoke, the chill of a sinister menace; but in the weirdness of the ceremony that followed, he almost lost his apprehension of personal peril.
One by one, from the further end of the row in which he was standing, the silent Oumnis went forward and circled the strange plant, walking slowly within a few feet of the inert branches of poisonous green that resembled sleepy, half-coiled serpents. The Roccalim preserved a torpid stillness, without the least sign of animation, as Oumni after Oumni finished his perilous circuit and retired to the further side of the room, there to stand and watch the perambulations of the others.
About twenty of the white Immortals had undergone this ordeal, when Howard’s turn came. Resolutely, with a sense of unreality and grotesquery rather than actual danger, he stepped forward and began his circuit of the living plant. The Oumnis looked on like alabaster statues; and all was utterly still and silent, except for a muffled, mysterious throbbing as of underworld machinery at a distance.
Howard moved on in an arc, watching the green branches with a growing tenseness. He had gone half the required distance when he felt, rather than saw, a flash of swift, intense light that appeared to stab downward from the cavern roof and strike the lumpish yellow bole of the Roccalim. The light faded in the merest fraction of time, leaving Howard in doubt as to whether he had really seen it.
Then, as he went on, he perceived with startled horror that the trailing tentacular boughs had begun to twitch and quiver, and were lifting slowly from the floor and waving toward him. On and on they came, rising and straightening, like a mass of ropy kelp that flows in an ocean-stream. They reached him, they slithered with reptilian ease about his body, and touched his face with their venomous-looking tips, clammy and inquisitive.
Howard drew back, wrenching himself away from the waving mass, and found Agvur at his elbow. The face of the Mercutian was touched with an unearthly gloating; and his iridescent locks floated upward, quivering with weird restlessness, like the Roccalim branches.
At that moment, it came to Howard that his fate had been predetermined from the beginning; that the swift, evanescent flash of light, proceeding from an unknown source, had perhaps served in some manner to irritate the living plant and provoke the action of its tentacular limbs.
Swift anger flared in the earth-man, but he repressed it. He must be cautious, must watch for an opportunity—even the slimmest—of escape. By giving the impression that he was resigned, he might throw his captors off their guard.