Da Costa, who had come aboard unnoticed by either of us, now tapped me on the arm.

“Doctair Goodwin,” he said, “can I see you in my cabin, sair?”

At last, then, he was going to speak. I followed him.

“Doctair,” he said, when we had entered, “this is a veree strange thing that has happened to Olaf. Veree strange. An’ the natives of Ponape, they have been very much excite’ lately.

“Of what they fear I know nothing, nothing!” Again that quick, furtive crossing of himself. “But this I have to tell you. There came to me from Ranaloa last month a man, a Russian, a doctair, like you. His name it was Marakinoff. I take him to Ponape an’ the natives there they will not take him to the Nan-Matal where he wish to go no! So I take him. We leave in a boat, wit’ much instrument carefully tied up. I leave him there wit’ the boat an’ the food. He tell me to tell no one an’ pay me not to. But you are a friend an’ Olaf he depend much upon you an’ so I tell you, sair.”

“You know nothing more than this, Da Costa?” I asked. “Nothing of another expedition?”

“No,” he shook his head vehemently. “Nothing more.”

“Hear the name Throckmartin while you were there?” I persisted.

“No,” his eyes were steady as he answered but the pallor had crept again into his face.

I was not so sure. But if he knew more than he had told me why was he afraid to speak? My anxiety deepened and later I sought relief from it by repeating the conversation to O’Keefe.

“A Russian, eh,” he said. “Well, they can be damned nice, or damned otherwise. Considering what you did for me, I hope I can look him over before the Dolphin shows up.”

Next morning we raised Ponape, without further incident, and before noon the Suwarna and the Brunhilda had dropped anchor in the harbour. Upon the excitement and manifest dread of the natives, when we sought among them for carriers and workmen to accompany us, I will not dwell. It is enough to say that no payment we offered could induce a single one of them to go to the Nan-Matal. Nor would they say why.

Finally it was agreed that the Brunhilda should be left in charge of a half-breed Chinaman, whom both Da Costa and Huldricksson knew and trusted. We piled her long-boat up with my instruments and food and camping equipment. The Suwarna took us around to Metalanim Harbour, and there, with the tops of ancient sea walls deep in the blue water beneath us, and the ruins looming up out of the mangroves, a scant mile from us, left us.

Then with Huldricksson manipulating our small sail, and Larry at the rudder, we rounded the titanic wall that swept down into the depths, and turned at last into the canal that Throckmartin, on his map, had marked as that which, running between frowning Nan-Tauach and its satellite islet, Tau, led straight to the gate of the place of ancient mysteries.

And as we entered that channel we were enveloped by a silence; a silence so intense, so weighted that it seemed to have substance; an alien silence that clung and stifled and still stood aloof from us the living. It was a stillness, such as might follow the long tramping of millions into the grave; it was paradoxical as it may be filled with the withdrawal of life.

Standing down in the chambered depths of the Great Pyramid I had known something of such silence but never such intensity as this. Larry felt it and I saw him look at me askance. If Olaf, sitting in the bow, felt it, too, he gave no sign; his blue eyes, with again the glint of ice within them, watched the channel before us.

As we passed, there arose upon our left sheer walls of black basalt blocks, cyclopean, towering fifty feet or more, broken here and there by the sinking of their deep foundations.

In front of us the mangroves widened out and filled the canal. On our right the lesser walls of Tau, sombre blocks smoothed and squared and set with a cold, mathematical nicety that filled me with vague awe, slipped by. Through breaks I caught glimpses of dark ruins and of great fallen stones that seemed to crouch and menace us, as we passed. Somewhere there, hidden, were the seven globes that poured the moon fire down upon the Moon Pool.

Now we were among the mangroves and, sail down, the three of us pushed and pulled the boat through their tangled roots and branches. The noise of our passing split the silence like a profanation, and from the ancient bastions came murmurs forbidding, strangely sinister. And now we were through, floating on a little open space of shadow-filled water. Before us lifted the gateway of Nan-Tauach, gigantic, broken, incredibly old; shattered portals through which had passed men and women of earth’s dawn; old with a weight of years that pressed leadenly upon the eyes that looked upon it, and yet was in some curious indefinable way menacingly defiant.

Beyond the gate, back from the portals, stretched a flight of enormous basalt slabs, a giant’s stairway indeed; and from each side of it marched the high walls that were the Dweller’s pathway. None of us spoke as we grounded the boat and dragged it upon a half-submerged pier. And when we did speak it was in whispers.

“What next?” asked Larry.

“I think we ought to take a look around,” I replied in the same low tones. “We’ll climb the wall here and take a flash about. The whole place ought to be plain as day from that height.”

Huldricksson, his blue eyes alert, nodded. With the greatest difficulty we clambered up the broken blocks.

To the east and south of us, set like children’s blocks in the midst of the sapphire sea, lay dozens of islets, none of them covering more than two square miles of surface; each of them a perfect square or oblong within its protecting walls.

On none was there sign of life, save for a few great birds that hovered here and there, and gulls dipping in the blue waves beyond.

We turned our gaze down upon the island on which we stood. It was, I estimated, about three-quarters of a mile square. The sea wall enclosed it. It was really an enormous basalt-sided open cube, and within it two other open cubes. The enclosure between the first and second wall was stone paved, with here and there a broken pillar and long stone benches. The hibiscus, the aloe tree, and a number of small shrubs had found place, but seemed only to intensify its stark loneliness.

“Wonder where the Russian can be?” asked Larry.

I shook my head. There was no sign of life here. Had Marakinoff gone or had the Dweller taken him, too? Whatever had happened, there was no trace of him below us or on any of the islets within our range of vision. We scrambled down the side of the gateway. Olaf looked at me wistfully.

“We start the search now, Olaf,” I said. “And first, O’Keefe, let us see whether the grey stone is really here. After that we will set up camp, and while I unpack, you and Olaf search the island. It won’t take long.”

Larry gave a look at his service automatic and grinned. “Lead on, Macduff,” he said. We made our way up the steps, through the outer enclosures and into the central square, I confess to a fire of scientific curiosity and eagerness tinged with a dread that O’Keefe’s analysis might be true. Would we find the moving slab and, if so, would it be as Throckmartin had described? If so, then even Larry would have to admit that here was something that theories of gases and luminous emanations would not explain; and the first test of the whole amazing story would be passed. But if not And there before us, the faintest tinge of grey setting it apart from its neighbouring blocks of basalt, was the moon door!

There was no mistaking it. This was, in very deed, the portal through which Throckmartin had seen pass that gloriously dreadful apparition he called the Dweller. At its base was the curious, seemingly polished cup-like depression within which, my lost friend had told me, the opening door swung.

What was that portal more enigmatic than was ever sphinx? And what lay beyond it? What did that smooth stone, whose wan deadness whispered of ages-old corridors of time opening out into alien, unimaginable vistas, hide? It had cost the world of science Throckmartin’s great brain as it had cost Throckmartin those he loved. It had drawn me to it in search of Throckmartin and its shadow had fallen upon the soul of Olaf the Norseman; and upon what thousands upon thousands more I wondered, since the brains that had conceived it had vanished with their secret knowledge?

What lay beyond it?

I stretched out a shaking hand and touched the surface of the slab. A faint thrill passed through my hand and arm, oddly unfamiliar and as oddly unpleasant; as of electric contact holding the very essence of cold. O’Keefe, watching, imitated my action. As his fingers rested on the stone his face filled with astonishment.

“It’s the door?” he asked. I nodded. There was a low whistle from him and he pointed up toward the top of the grey stone. I followed the gesture and saw, above the moon door and on each side of it, two gently curving bosses of rock, perhaps a foot in diameter.

“The moon door’s keys,” I said.

“It begins to look so,” answered Larry. “If we can find them,” he added.

“There’s nothing we can do till moonrise,” I replied. “And we’ve none too much time to prepare as it is. Come!”

A little later we were beside our boat. We lightered it, set up the tent, and as it was now but a short hour to sundown I bade them leave me and make their search. They went off together, and I busied myself with opening some of the paraphernalia I had brought with me.

First of all I took out the two Becquerel ray-condensers that I had bought in Sydney. Their lenses would collect and intensify to the fullest extent any light directed upon them. I had found them most useful in making spectroscopic analysis of luminous vapours, and I knew that at Yerkes Observatory splendid results had been obtained from them in collecting the diffused radiance of the nebulae for the same purpose.

If my theory of the grey slab’s mechanism were correct, it was practically certain that with the satellite only a few nights past the full we could concentrate enough light on the bosses to open the rock. And as the ray streams through the seven globes described by Throckmartin would be too weak to energize the Pool, we could enter the chamber free from any fear of encountering its tenant, make our preliminary observations and go forth before the moon had dropped so far that the concentration in the condensers would fall below that necessary to keep the portal from closing.

I took out also a small spectroscope, and a few other instruments for the analysis of certain light manifestations and the testing of metal and liquid. Finally, I put aside my emergency medical kit.

I had hardly finished examining and adjusting these before O’Keefe and Huldricksson returned. They reported signs of a camp at least ten days old beside the northern wall of the outer court, but beyond that no evidence of others beyond ourselves on Nan-Tauach.

We prepared supper, ate and talked a little, but for the most part were silent. Even Larry’s high spirits were not in evidence; half a dozen times I saw him take out his automatic and look it over. He was more thoughtful than I had ever seen him. Once he went into the tent, rummaged about a bit and brought out another revolver which, he said, he had got from Da Costa, and a half-dozen clips of cartridges. He passed the gun over to Olaf.

At last a glow in the southeast heralded the rising moon. I picked up my instruments and the medical kit; Larry and Olaf shouldered each a short ladder that was part of my equipment, and, with our electric flashes pointing the way, walked up the great stairs, through the enclosures, and straight to the grey stone.

By this time the moon had risen and its clipped light shone full upon the slab. I saw faint gleams pass over it as of fleeting phosphorescence but so faint were they that I could not be sure of the truth of my observation.

We set the ladders in place. Olaf I assigned to stand before the door and watch for the first signs of its opening if open it should. The Becquerels were set within three-inch tripods, whose feet I had equipped with vacuum rings to enable them to hold fast to the rock.

I scaled one ladder and fastened a condenser over the boss; descended; sent Larry up to watch it, and, ascending the second ladder, rapidly fixed the other in its place. Then, with O’Keefe watchful on his perch, I on mine, and Olaf’s eyes fixed upon the moon door, we began our vigil. Suddenly there was an exclamation from Larry.

“Seven little lights are beginning to glow on this stone!” he cried.

But I had already seen those beneath my lens begin to gleam out with a silvery lustre. Swiftly the rays within the condenser began to thicken and increase, and as they did so the seven small circles waxed like stars growing out of the dusk, and with a queer curdled is the best word I can find to define it radiance entirely strange to me.

Beneath me I heard a faint, sighing murmur and then the voice of Huldricksson:

“It opens the stone turns

I began to climb down the ladder. Again came Olaf’s voice:

“The stone it is open ” And then a shriek, a wail of blended anguish and pity, of rage and despair and the sound of swift footsteps racing through the wall beneath me!

I dropped to the ground. The moon door was wide open, and through it I caught a glimpse of a corridor filled with a faint, pearly vaporous light like earliest misty dawn. But of Olaf I could see nothing! And even as I stood, gaping, from behind me came the sharp crack of a rifle; the glass of the condenser at Larry’s side flew into fragments; he dropped swiftly to the ground, the automatic in his hand flashed once, twice, into the darkness.

And the moon door began to pivot slowly, slowly back into its place!

I rushed toward the turning stone with the wild idea of holding it open. As I thrust my hands against it there came at my back a snarl and an oath and Larry staggered under the impact of a body that had flung itself straight at his throat. He reeled at the lip of the shallow cup at the base of the slab, slipped upon its polished curve, fell and rolled with that which had attacked him, kicking and writhing, straight through the narrowing portal into the passage!

Forgetting all else, I sprang to his aid. As I leaped I felt the closing edge of the moon door graze my side. Then, as Larry raised a fist, brought it down upon the temple of the man who had grappled with him and rose from the twitching body unsteadily to his feet, I heard shuddering past me a mournful whisper; spun about as though some giants hand had whirled me

The end of the corridor no longer opened out into the moonlit square of ruined Nan-Tauach. It was barred by a solid mass of glimmering stone. The moon door had closed!

O’Keefe took a stumbling step toward the barrier behind us. There was no mark of juncture with the shining walls; the slab fitted into the sides as closely as a mosaic.

“It’s shut all right,” said Larry. “But if there’s a way in, there’s a way out. Anyway, Doc, we’re right in the pew we’ve been heading for so why worry?” He grinned at me cheerfully. The man on the floor groaned, and he dropped to his knees beside him.

“Marakinoff!” he cried.

At my exclamation he moved aside, turning the face so I could see it. It was clearly Russian, and just as clearly its possessor was one of unusual force and intellect.

The strong, massive brow with orbital ridge unusually developed, the dominant, high-bridged nose, the straight lips with their more than suggestion of latent cruelty, and the strong lines of the jaw beneath a black, pointed beard all gave evidence that here was a personality beyond the ordinary.

“Couldn’t be anybody else,” said Larry, breaking in on my thoughts. “He must have been watching us over there from Chau-ta-leur’s vault all the time.”

Swiftly he ran practised hands over his body; then stood erect, holding out to me two wicked-looking magazine pistols and a knife. “He got one of my bullets through his right forearm, too,” he said. “Just a flesh wound, but it made him drop his rifle. Some arsenal, our little Russian scientist, what?”

I opened my medical kit. The wound was a slight one, and Larry stood looking on as I bandaged it.

“Got another one of those condensers?” he asked, suddenly. “And do you suppose Olaf will know enough to use it?”

“Larry,” I answered, “Olaf’s not outside! He’s in here somewhere!”

His jaw dropped.

“The hell you say!” he whispered.

“Didn’t you hear him shriek when the stone opened?” I asked.

“I heard him yell, yes,” he said. “But I didn’t know what was the matter. And then this wildcat jumped me ” He paused and his eyes widened. “Which way did he go?” he asked swiftly. I pointed down the faintly glowing passage.

“There’s only one way,” I said.

“Watch that bird close,” hissed O’Keefe, pointing to Marakinoff and pistol in hand stretched his long legs and raced away. I looked down at the Russian. His eyes were open, and he reached out a hand to me. I lifted him to his feet.

“I have heard,” he said. “We follow, quick. If you will take my arm, please, I am shaken yet, yes ” I gripped his shoulder without a word, and the two of us set off down the corridor after O’Keefe. Marakinoff was gasping, and his weight pressed upon me heavily, but he moved with all the will and strength that were in him.

As we ran I took hasty note of the tunnel. Its sides were smooth and polished, and the light seemed to come not from their surfaces, but from far within them giving to the walls an illusive aspect of distance and depth; rendering them in a peculiarly weird way spacious. The passage turned, twisted, ran down, turned again. It came to me that the light that illumined the tunnel was given out by tiny points deep within the stone, sprang from the points ripplingly and spread upon their polished faces.

There was a cry from Larry far ahead.

“Olaf!”

I gripped Marakinoff’s arm closer and we sped on. Now we were coming fast to the end of the passage. Before us was a high arch, and through it I glimpsed a dim, shifting luminosity as of mist filled with rainbows. We reached the portal and I looked into a chamber that might have been transported from that enchanted palace of the Jinn King that rises beyond the magic mountains of Kaf.

Before me stood O’Keefe and a dozen feet in front of him, Huldricksson, with something clasped tightly in his arms. The Norseman’s feet were at the verge of a shining, silvery lip of stone within whose oval lay a blue pool. And down upon this pool staring upward like a gigantic eye, fell seven pillars of phantom light one of them amethyst, one of rose, another of white, a fourth of blue, and three of emerald, of silver, and of amber. They fell each upon the azure surface, and I knew that these were the seven streams of radiance, within which the Dweller took shape now but pale ghosts of their brilliancy when the full energy of the moon stream raced through them.

Huldricksson bent and placed on the shining silver lip of the Pool that which he held and I saw that it was the body of a child! He set it there so gently, bent over the side and thrust a hand down into the water. And as he did so he moaned and lurched against the little body that lay before him. Instantly the form moved and slipped over the verge into the blue. Huldricksson threw his body over the stone, hands clutching, arms thrust deep down and from his lips issued a long-drawn, heart-shrivelling wail of pain and of anguish that held in it nothing human!

Close on its wake came a cry from Marakinoff.

“Catch him!” shouted the Russian. “Drag him back! Quick!”

He leaped forward, but before he could half clear the distance, O’Keefe had leaped too, had caught the Norseman by the shoulders and toppled him backward, where he lay whimpering and sobbing. And as I rushed behind Marakinoff I saw Larry lean over the lip of the Pool and cover his eyes with a shaking hand; saw the Russian peer into it with real pity in his cold eyes.

Then I stared down myself into the Moon Pool, and there, sinking, was a little maid whose dead face and fixed, terror-filled eyes looked straight into mine; and ever sinking slowly, slowly vanished! And I knew that this was Olaf’s Freda, his beloved yndling!

But where was the mother, and where had Olaf found his babe?

The Russian was first to speak.

“You have nitroglycerin there, yes?” he asked, pointing toward my medical kit that I had gripped unconsciously and carried with me during the mad rush down the passage. I nodded and drew it out.

“Hypodermic,” he ordered next, curtly; took the syringe, filled it accurately with its one one-hundredth of a grain dosage, and leaned over Huldricksson. He rolled up the sailor’s sleeves half-way to the shoulder. The arms were white with somewhat of that weird semitranslucence that I had seen on Throckmartin’s breast where a tendril of the Dweller had touched him; and his hands were of the same whiteness like a baroque pearl. Above the line of white, Marakinoff thrust the needle.

“He will need all his heart can do,” he said to me.

Then he reached down into a belt about his waist and drew from it a small, flat flask of what seemed to be lead. He opened it and let a few drops of its contents fall on each arm of the Norwegian. The liquid sparkled and instantly began to spread over the skin much as oil or gasoline dropped on water does only far more rapidly. And as it spread it drew a sparkling film over the marbled flesh and little wisps of vapour rose from it. The Norseman’s mighty chest heaved with agony. His hands clenched. The Russian gave a grunt of satisfaction at this, dropped a little more of the liquid, and then, watching closely, grunted again and leaned back. Huldricksson’s laboured breathing ceased, his head dropped upon Larry’s knee, and from his arms and hands the whiteness swiftly withdrew.

Marakinoff arose and contemplated us almost benevolently.

“He will all right be in five minutes,” he said. “I know. I do it to pay for that shot of mine, and also because we will need him. Yes.” He turned to Larry. “You have a poonch like a mule kick, my young friend,” he said. “Some time you pay me for that, too, eh?” He smiled; and the quality of the grimace was not exactly reassuring. Larry looked him over quizzically.

“You’re Marakinoff, of course,” he said. The Russian nodded, betraying no surprise at the recognition.

“And you?” he asked.

“Lieutenant O’Keefe of the Royal Flying Corps,” replied Larry, saluting. “And this gentleman is Dr. Walter T. Goodwin.”

Marakinoff’s face brightened.

“The American botanist?” he queried. I nodded.

“Ah,” cried Marakinoff eagerly, “but this is fortunate. Long I have desired to meet you. Your work, for an American, is most excellent; surprising. But you are wrong in your theory of the development of the Angiospermae from Cycadeoidea dacotensis. Da all wrong

I was interrupting him with considerable heat, for my conclusions from the fossil Cycadeoidea I knew to be my greatest triumph, when Larry broke in upon me rudely.

“Say,” he spluttered, “am I crazy or are you? What in damnation kind of a place and time is this to start an argument like that?

“Angiospermae, is it?” exclaimed Larry. “Hell!”

Marakinoff again regarded him with that irritating air of benevolence.

“You have not the scientific mind, young friend,” he said. “The poonch, yes! But so has the mule. You must learn that only the fact is important not you, not me, not this” he pointed to Huldricksson “or its sorrows. Only the fact, whatever it is, is real, yes. But” he turned to me “another time

Huldricksson interrupted him. The big seaman had risen stiffly to his feet and stood with Larry’s arm supporting him. He stretched out his hands to me.

“I saw her,” he whispered. “I saw mine Freda when the stone swung. She lay there just at my feet. I picked her up and I saw that mine Freda was dead. But I hoped and I thought maybe mine Helma was somewhere here, too, So I ran with mine yndling here ” His voice broke. “I thought maybe she was not dead,” he went on. “And I saw that” he pointed to the Moon Pool “and I thought I would bathe her face and she might live again. And when I dipped my hands within the life left them, and cold, deadly cold, ran up through them into my heart. And mine Freda she fell ” he covered his eyes, and dropping his head on O’Keefe’s shoulder, stood, racked by sobs that seemed to tear at his very soul.