The face of Carthoris of Helium gave no token of the emotions that convulsed him inwardly as he heard from the lips of Hal Vas that Helium was at war with Dusar, and that fate had thrown him into the service of the enemy.

That he might utilize this opportunity to the good of Helium scarce sufficed to outweigh the chagrin he felt that he was not fighting in the open at the head of his own loyal troops.

To escape the Dusarians might prove an easy matter; and then again it might not. Should they suspect his loyalty (and the loyalty of an impressed panthan was always open to suspicion), he might not find an opportunity to elude their vigilance until after the termination of the war, which might occur within days, or, again, only after long and weary years of bloodshed.

He recalled that history recorded wars in which actual military operations had been carried on without cessation for five or six hundred years, and even now there were nations upon Barsoom with which Helium had made no peace within the history of man.

The outlook was not cheering. He could not guess that within a few hours he would be blessing the fate that had thrown him into the service of Dusar.

"Ah!" exclaimed Hal Vas. "Here is my father now. Kaor! Vas Kor. Here is one you will be glad to meet — a doughty panthan — " He hesitated.

"Turjun," interjected Carthoris, seizing upon the first appellation that occurred to him.

As he spoke his eyes crossed quickly to the tall warrior who was entering the room. Where before had he seen that giant figure, that taciturn countenance, and the livid sword-cut from temple to mouth?

"Vas Kor," repeated Carthoris mentally. "Vas Kor!" Where had he seen the man before?

And then the noble spoke, and like a flash it all came back to Carthoris — the forward servant upon the landing-stage at Ptarth that time that he had been explaining the intricacies of his new compass to Thuvan Dihn; the lone slave that had guarded his own hangar that night he had left upon his ill-fated journey for Ptarth — the journey that had brought him so mysteriously to far Aaanthor.

"Vas Kor," he repeated aloud, "blessed be your ancestors for this meeting," nor did the Dusarian guess the wealth of meaning that lay beneath that hackneyed phrase with which a Barsoomian acknowledges an introduction.

"And blessed be yours, Turjun," replied Vas Kor.

Now came the introduction of Kar Komak to Vas Kor, and as Carthoris went through the little ceremony there came to him the only explanation he might make to account for the white skin and auburn hair of the bowman; for he feared that the truth might not be believed and thus suspicion be cast upon them both from the beginning.

"Kar Komak," he explained, "is, as you can see, a thern. He has wandered far from his icebound southern temples in search of adventure. I came upon him in the pits of Aaanthor; but though I have known him so short a time, I can vouch for his bravery and loyalty."

Since the destruction of the fabric of their false religion by John Carter, the majority of the therns had gladly accepted the new order of things, so that it was now no longer uncommon to see them mingling with the multitudes of red men in any of the great cities of the outer world, so Vas Kor neither felt nor expressed any great astonishment.

All during the interview Carthoris watched, catlike, for some indication that Vas Kor recognized in the battered panthan the erstwhile gorgeous Prince of Helium; but the sleepless nights, the long days of marching and fighting, the wounds and the dried blood had evidently sufficed to obliterate the last remnant of his likeness to his former self; and then Vas Kor had seen him but twice in all his life. Little wonder that he did not know him.

During the evening Vas Kor announced that on the morrow they should depart north toward Dusar, picking up recruits at various stations along the way.

In a great field behind the house a flier lay — a fair-sized cruiser-transport that would accommodate many men, yet swift and well armed also. Here Carthoris slept, and Kar Komak, too, with the other recruits, under guard of the regular Dusarian warriors that manned the craft.

Toward midnight Vas Kor returned to the vessel from his son's house, repairing at once to his cabin. Carthoris, with one of the Dusarians, was on watch. It was with difficulty that the Heliumite repressed a cold smile as the noble passed within a foot of him — within a foot of the long, slim, Heliumitic blade that swung in his harness.

How easy it would have been! How easy to avenge the cowardly trick that had been played upon him — to avenge Helium and Ptarth and Thuvia!

But his hand moved not toward the dagger's hilt, for first Vas Kor must serve a better purpose — he might know where Thuvia of Ptarth lay hidden now, if it had truly been Dusarians that had spirited her away during the fight before Aaanthor.

And then, too, there was the instigator of the entire foul plot. He must pay the penalty; and who better than Vas Kor could lead the Prince of Helium to Astok of Dusar?

Faintly out of the night there came to Carthoris's ears the purring of a distant motor. He scanned the heavens.

Yes, there it was far in the north, dimly outlined against the dark void of space that stretched illimitably beyond it, the faint suggestion of a flier passing, unlighted, through the Barsoomian night.

Carthoris, knowing not whether the craft might be friend or foe of Dusar, gave no sign that he had seen, but turned his eyes in another direction, leaving the matter to the Dusarian who stood watch with him.

Presently the fellow discovered the oncoming craft, and sounded the low alarm which brought the balance of the watch and an officer from their sleeping silks and furs upon the deck near by.

The cruiser-transport lay without lights, and, resting as she was upon the ground, must have been entirely invisible to the oncoming flier, which all presently recognized as a small craft.

It soon became evident that the stranger intended making a landing, for she was now spiraling slowly above them, dropping lower and lower in each graceful curve.

"It is the Thuria," whispered one of the Dusarian warriors. "I would know her in the blackness of the pits among ten thousand other craft."

"Right you are!" exclaimed Vas Kor, who had come on deck. And then he hailed:

"Kaor, Thuria!"

"Kaor!" came presently from above after a brief silence. Then: "What ship?"

"Cruiser-transport Kalksus, Vas Kor of Dusar."

"Good!" came from above. "Is there safe landing alongside?"

"Yes, close in to starboard. Wait, we will show our lights," and a moment later the smaller craft settled close beside the Kalksus, and the lights of the latter were immediately extinguished once more.

Several figures could be seen slipping over the side of the Thuria and advancing toward the Kalksus. Ever suspicious, the Dusarians stood ready to receive the visitors as friends or foes as closer inspection might prove them. Carthoris stood quite near the rail, ready to take sides with the new-comers should chance have it that they were Heliumites playing a bold stroke of strategy upon this lone Dusarian ship. He had led like parties himself, and knew that such a contingency was quite possible.

But the face of the first man to cross the rail undeceived him with a shock that was not at all unpleasurable — it was the face of Astok, Prince of Dusar.

Scarce noticing the others upon the deck of the Kalksus, Astok strode forward to accept Vas Kor's greeting, then he summoned the noble below. The warriors and officers returned to their sleeping silks and furs, and once more the deck was deserted except for the Dusarian warrior and Turjun, the panthan, who stood guard.

The latter walked quietly to and fro. The former leaned across the rail, wishing for the hour that would bring him relief. He did not see his companion approach the lights of the cabin of Vas Kor. He did not see him stoop with ear close pressed to a tiny ventilator.

"May the white apes take us all," cried Astok ruefully, "if we are not in as ugly a snarl as you have ever seen! Nutus thinks that we have her in hiding far away from Dusar. He has bidden me bring her here."

He paused. No man should have heard from his lips the thing he was trying to tell. It should have been for ever the secret of Nutus and Astok, for upon it rested the safety of a throne. With that knowledge any man could wrest from the Jeddak of Dusar whatever he listed.

But Astok was afraid, and he wanted from this older man the suggestion of an alternative. He went on.

"I am to kill her," he whispered, looking fearfully around. "Nutus merely wishes to see the body that he may know his commands have been executed. I am now supposed to be gone to the spot where we have her hidden that I may fetch her in secrecy to Dusar. None is to know that she has ever been in the keeping of a Dusarian. I do not need to tell you what would befall Dusar should Ptarth and Helium and Kaol ever learn the truth."

The jaws of the listener at the ventilator clicked together with a vicious snap. Before he had but guessed at the identity of the subject of this conversation. Now he knew. And they were to kill her! His muscular fingers clenched until the nails bit into the palms.

"And you wish me to go with you while you fetch her to Dusar," Vas Kor was saying. "Where is she?"

Astok bent close and whispered into the other's ear. The suggestion of a smile crossed the cruel features of Vas Kor. He realized the power that lay within his grasp. He should be a jed at least.

"And how may I help you, my Prince?" asked the older man suavely.

"I cannot kill her," said Astok. "Issus! I cannot do it! When she turns those eyes upon me my heart becomes water."

Vas Kor's eyes narrowed.

"And you wish — " He paused, the interrogation unfinished, yet complete.

Astok nodded.

"You do not love her," he said.

"But I love my life — though I am only a lesser noble," he concluded meaningly.

"You shall be a greater noble — a noble of the first rank!" exclaimed Astok.

"I would be a jed," said Vas Kor bluntly.

Astok hesitated.

"A jed must die before there can be another jed," he pleaded.

"Jeds have died before," snapped Vas Kor. "It would doubtless be not difficult for you to find a jed you do not love, Astok — there are many who do not love you."

Already Vas Kor was commencing to presume upon his power over the young prince. Astok was quick to note and appreciate the subtle change in his lieutenant. A cunning scheme entered his weak and wicked brain.

"As you say, Vas Kor!" he exclaimed. "You shall be a jed when the thing is done," and then, to himself: "Nor will it then be difficult for me to find a jed I do not love."

"When shall we return to Dusar?" asked the noble.

"At once," replied Astok. "Let us get under way now — there is naught to keep you here?"

"I had intended sailing on the morrow, picking up such recruits as the various Dwars of the Roads might have collected for me, as we returned to Dusar."

"Let the recruits wait," said Astok. "Or, better still, come you to Dusar upon the Thuria, leaving the Kalksus to follow and pick up the recruits."

"Yes," acquiesced Vas Kor; "that is the better plan. Come; I am ready," and he rose to accompany Astok to the latter's flier.

The listener at the ventilator came to his feet slowly, like an old man. His face was drawn and pinched and very white beneath the light copper of his skin. She was to die! And he helpless to avert the tragedy. He did not even know where she was imprisoned.

The two men were ascending from the cabin to the deck. Turjun, the panthan, crept close to the companionway, his sinuous fingers closing tightly upon the hilt of his dagger. Could he despatch them both before he was overpowered? He smiled. He could slay an entire utan of her enemies in his present state of mind.

They were almost abreast of him now. Astok was speaking.

"Bring a couple of your men along, Vas Kor," he said. "We are short-handed upon the Thuria, so quickly did we depart."

The panthan's fingers dropped from the dagger's hilt. His quick mind had grasped here a chance for succouring Thuvia of Ptarth. He might be chosen as one to accompany the assassins, and once he had learned where the captive lay he could dispatch Astok and Vas Kor as well as now. To kill them before he knew where Thuvia was hid was simply to leave her to death at the hands of others; for sooner or later Nutus would learn her whereabouts, and Nutus, Jeddak of Dusar, could not afford to let her live.

Turjun put himself in the path of Vas Kor that he might not be overlooked. The noble aroused the men sleeping upon the deck, but always before him the strange panthan whom he had recruited that same day found means for keeping himself to the fore.

Vas Kor turned to his lieutenant, giving instruction for the bringing of the Kalksus to Dusar, and the gathering up of the recruits; then he signed to two warriors who stood close behind the padwar.

"You two accompany us to the Thuria," he said, "and put yourselves at the disposal of her dwar."

It was dark upon the deck of the Kalksus, so Vas Kor had not a good look at the faces of the two he chose; but that was of no moment, for they were but common warriors to assist with the ordinary duties upon a flier, and to fight if need be.

One of the two was Kar Komak, the bowman. The other was not Carthoris.

The Heliumite was mad with disappointment. He snatched his dagger from his harness; but already Astok had left the deck of the Kalksus, and he knew that before he could overtake him, should he dispatch Vas Kor, he would be killed by the Dusarian warriors, who now were thick upon the deck. With either one of the two alive Thuvia was in as great danger as though both lived — it must be both!

As Vas Kor descended to the ground Carthoris boldly followed him, nor did any attempt to halt him, thinking, doubtless, that he was one of the party.

After him came Kar Komak and the Dusarian warrior who had been detailed to duty upon the Thuria. Carthoris walked close to the left side of the latter. Now they came to the dense shadow under the side of the Thuria. It was very dark there, so that they had to grope for the ladder.

Kar Komak preceded the Dusarian. The latter reached upward for the swinging rounds, and as he did so steel fingers closed upon his windpipe and a steel blade pierced the very centre of his heart.

Turjun, the panthan, was the last to clamber over the rail of the Thuria, drawing the rope ladder in after him.

A moment later the flier was rising rapidly, headed for the north.

At the rail Kar Komak turned to speak to the warrior who had been detailed to accompany him. His eyes went wide as they rested upon the face of the young man whom he had met beside the granite cliffs that guard mysterious Lothar. How had he come in place of the Dusarian?

A quick sign, and Kar Komak turned once more to find the Thuria's dwar that he might report himself for duty. Behind him followed the panthan.

Carthoris blessed the chance that had caused Vas Kor to choose the bowman of all others, for had it been another Dusarian there would have been questions to answer as to the whereabouts of the warrior who lay so quietly in the field beyond the residence of Hal Vas, Dwar of the Southern Road; and Carthoris had no answer to that question other than his sword point, which alone was scarce adequate to convince the entire crew of the Thuria.

The journey to Dusar seemed interminable to the impatient Carthoris, though as a matter of fact it was quickly accomplished. Some time before they reached their destination they met and spoke with another Dusarian war flier. From it they learned that a great battle was soon to be fought south-east of Dusar.

The combined navies of Dusar, Ptarth and Kaol had been intercepted in their advance toward Helium by the mighty Heliumitic navy — the most formidable upon Barsoom, not alone in numbers and armament, but in the training and courage of its officers and warriors, and the zitidaric proportions of many of its monster battleships.

Not for many a day had there been the promise of such a battle. Four jeddaks were in direct command of their own fleets — Kulan Tith of Kaol, Thuvan Dihn of Ptarth, and Nutus of Dusar upon one side; while upon the other was Tardos Mors, Jeddak of Helium. With the latter was John Carter, Warlord of Mars.

From the far north another force was moving south across the barrier cliffs — the new navy of Talu, Jeddak of Okar, coming in response to the call from the warlord. Upon the decks of the sullen ships of war black-bearded yellow men looked over eagerly toward the south. Gorgeous were they in their splendid cloaks of orluk and apt. Fierce, formidable fighters from the hothouse cities of the frozen north.

And from the distant south, from the sea of Omean and the cliffs of gold, from the temples of the therns and the garden of Issus, other thousands sailed into the north at the call of the great man they all had learned to respect, and, respecting, love. Pacing the flagship of this mighty fleet, second only to the navy of Helium, was the ebon Xodar, Jeddak of the First Born, his heart beating strong in anticipation of the coming moment when he should hurl his savage crews and the weight of his mighty ships upon the enemies of the warlord.

But would these allies reach the theatre of war in time to be of avail to Helium? Or, would Helium need them?

Carthoris, with the other members of the crew of the Thuria, heard the gossip and the rumours. None knew of the two fleets, the one from the south and the other from the north, that were coming to support the ships of Helium, and all of Dusar were convinced that nothing now could save the ancient power of Helium from being wiped for ever from the upper air of Barsoom.

Carthoris, too, loyal son of Helium that he was, felt that even his beloved navy might not be able to cope successfully with the combined forces of three great powers.

Now the Thuria touched the landing-stage above the palace of Astok. Hurriedly the prince and Vas Kor disembarked and entered the drop that would carry them to the lower levels of the palace.

Close beside it was another drop that was utilized by common warriors. Carthoris touched Kar Komak upon the arm.

"Come!" he whispered. "You are my only friend among a nation of enemies. Will you stand by me?"

"To the death," replied Kar Komak.

The two approached the drop. A slave operated it.

"Where are your passes?" he asked.

Carthoris fumbled in his pocket pouch as though in search of them, at the same time entering the cage. Kar Komak followed him, closing the door. The slave did not start the cage downward. Every second counted. They must reach the lower level as soon as possible after Astok and Vas Kor if they would know whither the two went.

Carthoris turned suddenly upon the slave, hurling him to the opposite side of the cage.

"Bind and gag him, Kar Komak!" he cried.

Then he grasped the control lever, and as the cage shot downward at sickening speed, the bowman grappled with the slave. Carthoris could not leave the control to assist his companion, for should they touch the lowest level at the speed at which they were going, all would be dashed to instant death.

Below him he could now see the top of Astok's cage in the parallel shaft, and he reduced the speed of his to that of the other. The slave commenced to scream.

"Silence him!" cried Carthoris.

A moment later a limp form crumpled to the floor of the cage.

"He is silenced," said Kar Komak.

Carthoris brought the cage to a sudden stop at one of the higher levels of the palace. Opening the door, he grasped the still form of the slave and pushed it out upon the floor. Then he banged the gate and resumed the downward drop.

Once more he sighted the top of the cage that held Astok and Vas Kor. An instant later it had stopped, and as he brought his car to a halt, he saw the two men disappear through one of the exits of the corridor beyond.