TARZAN, D’Arnot, Herkuf, and Lavac hastened through the air chamber out onto the bottom of the lake to the spot where Helen had been left to await their return; but she was not there, though the casket lay undisturbed where Herkuf had hidden it. There was no clew to her whereabouts; and the men were at a loss as to the direction in which they should search. They dared not separate, and so they followed Tarzan as he wandered here and there about the garden of the ptomes looking for some trace of the missing girl. While they were thus engaged, the ape-man’s attention was attracted by the approach of several large marine animals the upper portions of which closely resembled the head and neck of a horse. There were six of them, and it was soon evident that they meant to attack. That they were extremely dangerous, Herkuf knew and the others soon realized, for they were as large as a man; and each was armed with a long, sharp horn which grew upward from the lower ends of their snouts.
Two of them attacked Tarzan, and one each the other three men, while the sixth circled about as though awaiting an opening through which it might take an antagonist unaware. Tarzan succeeded in dispatching one of those attacking him; and d’Arnot seemed to be experiencing no great difficulty with his. Lavac was hard pressed; but when he saw the sixth sea horse gliding up behind d’Arnot to impale him on its horn he turned to the rescue of his companion; as he did so, exposing himself to the attack of the sea horse with which he had been engaged.
It was an act of heroism on the part of the man who had wronged d’Arnot, an act that made full amends but cost a brave life, for the sea horse he had abandoned to come to d’Arnot’s rescue plunged its powerful horn between his shoulders. Thus died Lieutenant Jacques Lavac.
As Tarzan thrust his trident into the heart of a second antagonist, the remaining beasts swam away in defeat. D’Arnot dropped to one knee beside Lavac and examined him as best he could; then he stood up and shook his head. The others understood; and sadly the three turned away and resumed their fruitless search, wondering, possibly, which would be the next to die in this land of danger and sudden death.
At last, by signs, they agreed to abandon the search, for even d’Arnot now felt certain that Helen must be dead; and, following Herkuf, who had brought the casket with him, they scaled the steep ascent to the lake shore, emerging at last a short distance below Ashair.
D’Arnot was heart broken; Herkuf was filled with renewed hope, for he knew what the casket contained and what it meant to him; only Tarzan of the Apes was unmoved. “Brulor is dead,” he said, “and The Father of Diamonds stolen. I must return to Thobos as I promised Herat.”
“It will not be necessary, if you wish to remain here and search for your other friends,” said Herkuf. “I shall explain everything to Herat, and for what you have done to restore this to him, he will grant you any favor.” He tapped the lid of the casket.
“What is it?” asked d’Arnot.
“In this is the true Father of Diamonds,” replied Herkuf. “Many years ago, Chon, the true god, was making his annual tour of Holy Horus in a great galley. As was the custom, he carried The Father of Diamonds with him. Queen Atka, jealous of Herat, attacked and sank the galley; and Chon was drowned, while I was taken prisoner. As you, Tarzan, will recall, when we found the wrecked galley at the bottom of Horus, I recognized it and retrieved the casket that had lain there so many years. Now I am sure that if we restore The Father of Diamonds to Thobos, Herat will grant any request we may make, for without The Father of Diamonds, Thobos has been without a god all these years.”
“You and Herkuf take the casket to Herat,” said d’Arnot to Tarzan. “I cannot leave here. Helen may live and may come ashore. Somehow, I can’t believe that she is dead.”
“Take the casket to Herat, Herkuf,” directed Tarzan. “I shall remain here with d’Arnot. Tell Herat I’ll come back to Thobos if he wishes me to. I may come any way. We’ll have to have a galley to get out of Tuen-Baka.”
Herkuf made good time to Thobos, nor was there any delay on the part of Herat in granting him an audience when the king learned that he claimed to be the long lost priest, Herkuf, and that he had The Father of Diamonds in his possession; and it was not long after his arrival at the city gate before Herkuf stood before the king.
“Here, O Herat, is the sacred casket with The Father of Diamonds. Had it not been for the man, Tarzan, it would never have been recovered. I know that he and his friends are in grave peril, for they are close to Ashair. Will you not send galleys and warriors to rescue them?”
“With this,” cried Herat, touching the casket, “our forces cannot lose, for we shall again have the god upon our side.” He turned to one of his aides. “Let all the war galleys be prepared and manned. We shall attack Ashair at once; and at last the followers of the true god, Chon, shall prevail; and the traitors and the wicked shall be destroyed. All that is lacking to our complete triumph is the presence in the flesh of the holy Chon.”
“He will be with us in spirit,” Herkuf reminded him.
So King Herat put out from Thobos with many war galleys, to avenge the wrong that Atka had done his god and to succor the strangers who had been instrumental in recovering the true Father of Diamonds from the bottom of Holy Horus; and Queen Mentheb and her ladies waved to them from the quay and wished them godspeed.
The true god, Chon, and his priests were gathered in the cavern temple on the shore of Horus. The three prisoners stood below the altar before the throne. At a word from Chon, several priests seized Gregory, stripped his clothing from him, and threw him to his back across the altar. Chon rose from his throne and stood above him.
“From the entrails of this man let the oracle speak!” he cried. He paused, and the priests intoned a weird chant, while Helen and Magra looked on, horrified and helpless.
“No! No!” cried Helen. “You must not! My father has done nothing to wrong you.”
“Then why is he here in forbidden Tuen-Baka?” demanded Chon.
“I have told you time and again that we came here only in search of my brother, who is lost.”
“Why was your brother here?”
“He came with a scientific expedition of exploration,” explained the girl.
Chon shook his head. “It is death to all who enter forbidden Tuen-Baka from the outer world,” he replied. “But we know why they really came. They came only for The Father of Diamonds. To us it is the emblem of godhood; to them it is a priceless object of incalculable value. There is nothing that they would not do to possess it. They would defile our temples; they would murder us. The fact that they could never succeed in obtaining it, does not lessen their guilt.”
“My father would not have done these things. He only wanted his son back. He cares nothing for your diamond.”
“There is no diamond where anyone can steal it,” said Chon, “for The Father of Diamonds lies at the bottom of Horus, lost forever. If I am wrong in thinking that you came solely to steal it, you shall go free. I am a just god.”
“But you are wrong,” urged Helen. “Won’t you please take my word for it? If you kill my father—oh, what good will it do you to find out later that you are wrong?”
“You may speak the truth,” replied Chon, “but you may lie. The oracle will not lie. From the entrails of this man the oracle shall speak. Priests of the true god, prepare the sacrifice!”
As the priests stretched Gregory across the altar and sprinkled a liquid over him, the others commenced a solemn chant; and Helen stretched her arms toward Chon.
“Oh, please!” she begged. “If you must have a sacrifice, take me, not my father.”
“Silence!” commanded Chon. “If you have lied, your time will come. Soon we shall know.”
After Herkuf left them, Tarzan and d’Arnot started back toward Ashair. They had no plan, nor much hope. If Helen lived, she might be in Ashair. If she were dead, d’Arnot did not care what fate befell him. As for Tarzan, he was seldom concerned beyond the present moment. Suddenly he was alert. He pointed toward a cliff ahead of them.
“One of Ungo’s apes just went into that cave,” he said. “Let’s take a look. The mangani are not ordinarily interested in caves. Something unusual may have impelled that one to enter; we’ll see what.”
“Oh, why bother?” queried d’Arnot. “We are not interested in apes.”
“I am interested in everything,” replied the ape-man.
Brian and Taask stumbled through the dark corridor to burst suddenly into the cavern temple upon the scene of Gregory’s impending sacrifice. At sight of them, Chon, the true god, recoiled, dropping his knife hand at his side.
“In the name of Isis!” he shouted. “Who dares interrupt?”
“Brian!” cried Helen.
“Helen!” The man started across the room toward his sister; but half a dozen priests sprang forward and seized him, and others intercepted Helen as she tried to run to meet him.
“Who are these men?” demanded Chon.
“One is my brother,” replied Helen. “Oh, Brian, tell him we don’t want their diamond.”
“Save your breath, man,” snapped Chon. “Only the oracle speaks the truth! On with the sacrifice to truth!”
“Marvellous! Stupendous!” exclaimed d’Arnot, as he and Tarzan entered the outer cavern of Chon’s temple.
“Yes,” admitted the ape-man, “but where is the mangani we saw coming in here. I smell many of them. They have just been in this cave. I wonder why?”
“Have you no soul?” demanded d’Arnot.
“I don’t know about that,” smiled Tarzan, “but I have a brain. Come on, let’s get after those apes. I detect the scent spoor of men, too. The stink of the apes is so strong that it almost hides the other.”
“I smell nothing,” said d’Arnot, as he followed Tarzan toward the opening at the far end of the cavern.
Chon was furious. “Let there be no more interruptions!” he cried. “There are many questions to be asked of the oracle. Let there be silence, too; if the oracle is to be heard, the man must be opened in silence.” Three times he raised and lowered the sacrificial knife above the prostrate Gregory. “Speak, oracle, that the truth may be known!”
As he placed the point of the knife at the lower extremity of the victim’s abdomen, the great apes, led by Ungo, streamed into the cavern; and once again the rite of human sacrifice was interrupted, as Chon and his priests looked, probably for the first time, at these hairy beast-men.
The sight of so many tarmangani and the strange garments of the priests confused and irritated the apes, with the result that they attacked without provocation, forgetting the injunction of Tarzan.
The surprised priests, who had been holding Gregory, released him; and he slipped from the altar to stand leaning against it in a state bordering on collapse. Chon raised his voice in impotent curses and commands, while all the others tried to fight off the attacking apes.
Zu-tho and Ga-un saw the two girls, and Zu-tho recalled that Ungo had run off with a she tarmangani; so, impelled by imitative desire, he seized Magra; and Ga-un, following the lead of his fellow, gathered up Helen; then the two apes sought to escape from the cavern with their prizes. Being confused, they chanced upon a different corridor from that by which they had entered the cavern, a corridor that rose steeply to a higher level.
Before anyone had been seriously injured by the apes, a commanding voice rang out from the rear of the cavern. “Dan-do, mangani!” it ordered in a tongue no other human knew, and the great apes wheeled about to see Tarzan standing in the entrance to the cavern. Even Chon ceased his cursing.
Tarzan surveyed the gathering in the temple. “We are all here but Helen, Magra, and Lavac,” he said, “and Lavac is dead.”
“The girls were here a minute ago,” said Gregory, as he hastily donned his clothes without interruption by Chon or the priests.
“They must have hidden somewhere when the apes came,” suggested Brian.
“Helen was here!” gasped d’Arnot. “She is not dead?”
“She was here,” Gregory assured him.
Brian was calling the girls loudly by name, but there was no reply. Chon was trying to gather his wits together.
Zu-tho and Ga-un dragged their captives through a steep, short corridor that ended in a third cavern with an arched opening that looked out over Horus far below. Zu-tho held Magra by the hair, while Ga-un dragged Helen along by one ankle. The apes stopped in the middle of the cavern and looked about. They didn’t know what to do with their prizes now that they had them. They released their holds upon the girls and jabbered at one another, and as they jabbered, Helen and Magra backed slowly away from them toward the opening overlooking the lake.
“These are Tarzan’s shes,” said Zu-tho. “Ungo and Tarzan will kill us.”
“Look at their hairless skins and little mouths,” said Ga-un. “They are hideous and no good. If we kill them and throw them into the water, Tarzan and Ungo will never know that we took them.”
Zu-tho thought that this was a good idea; so he advanced toward the girls, and Ga-un followed him.
“I kill!” growled Zu-tho, in the language of the great apes.
“I kill!” snarled Ga-un.
“I believe the beasts are going to kill us,” said Magra.
“I can almost hope so,” replied Helen.
“We’ll choose our own death,” cried Magra. “Follow me!”
As Magra spoke, she turned and ran toward the opening overlooking the lake; and Helen followed her. Zu-tho and Ga-un charged to seize them; but they were too late; and the girls leaped out into space over the waters of sacred Horus, far below; while Asharian warriors in a passing galley watched.