Cautiously the two men took three water suits and helmets from their pegs, gathered up three tridents, and crossed the room to the doorway on the opposite side without awakening a ptome. Once past the door, each donned a suit.
"The gods have been with us so far," whispered Herkuf, "and if we can pass through the air chamber without being discovered, we stand a good chance to succeed—if we are in time."
As the water rose to Helen's shoulders she finally gave up all thought of suicide. She would cling to life to the last moment. They might rob her of that; but they could not rob her of her courage, and as the water rose still higher she stepped to the lowest rung of the ladder.
Reminiscences rioted through her mind as she waited for death, and pleasant thoughts and bitter. She pondered the futility of man's quest for sudden wealth and of the evil and suffering it entailed. Of what avail would success be now to either Brian or Thorne if, by some chance, it should come to one of them? for one had lost his sister and, perhaps, his father; and the other had lost his mind. Now the water forced her up to a higher rung of the ladder. Step by step, she was climbing to her rendezvous with Death.
Herkuf and Tarzan passed safely through the air chamber out into the water of the lake. Through the garden of the ptomes they made their way toward the watery cell where Death was creeping relentlessly upon Helen Gregory, and dark shapes glided sinuously about them in this mysterious world of silence.
At last they reached the air chamber above Helen's cell; and Herkuf started the pump that would eject the water, but it seemed to both men that it would never empty the chamber. They knew that the water had been rising for hours in the death cell beneath them and that death might come to the girl before they reached her, if she were not already dead.
Just below them, clinging to the last few precious moments of life, Helen had ascended the ladder as far as she could go; but the water pursued her relentlessly. Already her head was touching the ceiling. She could climb no farther. The cold hand of Death caressed her cheek. Suddenly she became alert, listening. She heard noises in the chamber above. What might they signify? Not rescue, certainly; perhaps some new torture.
At last the air chamber was emptied. Tarzan and Herkuf attempted to raise the trap door leading into Helen's cell; but it defied their every effort, even the Herculean strength of the Lord of the Jungle. And what was happening, or had happened, in the cell below?—cell or tomb?
And while Tarzan and Herkuf labored with the trap door a ptome awoke and sat up upon his hard bench, rubbing his eyes. He had had a strange, disquieting dream in which enemies had passed through the room of the ptomes. He looked about to see if anyone was there who should not be. Mechanically, he looked for his water suit and helmet. They were gone, and two other pegs were empty. Instantly he awoke his fellows and disclosed his discovery, telling them of his dream. They were all much perturbed, for such things had never happened before in the memory of man. They started to investigate immediately, going first to the throne room, where they soon discovered that two of the prisoners were missing.
"Herkuf is gone and the man called Tarzan," said one.
"But three suits and tridents were taken," pointed out another.
By this time the prisoners were awake; and they questioned them, with many threats; but they learned nothing for the prisoners knew nothing, and were quite as surprised as the ptomes.
"I have it!" cried a ptome at last. "It is quite plain that they have gone to the little chamber in the lake to release the girl, that is why they took the extra suit. Quick! Into your helmets! In the name of Atka, hurry!"
"We must not all go, or the rest of the prisoners may escape as the others did," suggested one; so only six of them donned their suits and hurried into the waters of Horus in pursuit of the two missing prisoners. Armed as they were, with tridents and knives, they had no thought but that they could easily overcome and recapture their quarry.
For many precious minutes the trap door refused to yield to the efforts of Tarzan and Herkuf; but at last it gave way, and they threw it open. Looking down into the darkness, they at first saw nothing; then Tarzan espied, dimly, a wan face apparently floating on the surface of the water. Were they, after all, too late? Was this the face of a dead girl?
Holding to the ladder and floating with her nose just above the water, Helen heard increasing sounds of activity just above her; then the trap door was lifted, and she saw two ptomes looking down at her. As they dragged her into the air chamber, she guessed that they had come to inflict some new torture.
They helped her to don the extra water suit, and led her out of the air chamber into the lake. In their suits and helmets, she did not recognize them; and as there was no means of communication, she went on with them, ignorant of their identity, wondering what next Fate had in store for her.
As Herkuf led them away from the vicinity of the temple, the pursuing ptomes discovered them and hurried to overtake them. In the silence of the watery depths, no sound reached the ears of the fugitives; and they were ignorant of the danger approaching from behind; until, finally, Tarzan, always the wary jungle beast, looked back and saw the ptomes approaching. He touched Herkuf and Helen, and pointed; then he gathered them together, so that they all stood back to back to await the assault of the enemy he well knew they could not outdistance in flight. What the outcome of such a battle would be, he could not even guess. He knew that they were all unused to fighting in such a medium and with such weapons. A single rent in a suit might mean death by drowning, and doubtless their antagonists were adepts in the use of tridents. What he did not know was that the ptomes were as unused to underwater fighting as was he. Sometimes they had to defend themselves from the more dangerous denizens of the deep, but never had they been called upon to face human antagonists and weapons identical to their own.
So it was that Tarzan and Herkuf drew first blood; and now, for the first time, Helen realized that she might be in the hands of friends; yet that seemed entirely implausible, for how could she have friends among the ptomes?
With two of their number dead in the first encounter with the enemy, the four remaining ptomes became more wary. They circled cautiously, waiting for an opening; but there seemed no opening in the impregnable defense of the three, who could not be lured from the compact formation that presented a trident on every front. Suddenly one of the ptomes leaped above the heads of the quarry to attack them from a new angle; and as he did so, his fellows rushed in. But they rushed too close, and two of them went to their deaths on the tridents of Herkuf and Tarzan; then the one above them floated down and struck at the ape-man. As he did so, Helen jabbed suddenly upward with her trident, catching the fellow squarely in the chest. He wriggled horribly, like a speared fish, and then sank limply at her feet. The girl had to steel herself to keep from fainting.
With his fellows dead, the remaining ptome turned and fled toward the temple; but Tarzan dared not let him escape to bring reinforcements; so he pursued him, feeling like one in a bad dream, who makes strenuous efforts but accomplishes little or nothing. However, the ptome had the same watery medium to contend with; but not the giant muscles to overcome it that his pursuer possessed; so gradually Tarzan gained on him, while Herkuf and Helen followed in his wake.
When the ptome realized that he could not make good his escape, he turned at bay and prepared to fight; and Tarzan found him the most dangerous antagonist of all, for he was fighting with the desperation of a cornered rat. It was the strangest duel the ape-man had ever fought. The weird, mysterious silence of the depths; the grotesque medium that retarded his every movement; all baffled him. He was accustomed to fighting on one plane and not having antagonists leap above his head and thrust down at him, as the ptome suddenly did; but he fended the thrust, and seized his foe by the ankle. The ptome struggled to free himself, thrusting savagely with his trident; but at last Tarzan was sure of himself, as he dragged the lesser priest toward him.