Part 4

"As the centuries passed, the atmosphere continued to thin," Staunton went on, "so the Ancients took care to preserve what was left. Gral-Thala is in the fertile part of the Moon, and lies in a vast valley completely surrounded by a lofty mountain range. By means of the superior engineering knowledge of the Ancients, they built a lofty wall or barrier along the crest of the range so that its top is miles above the level of the valley floor. They then sucked all the air within the Great Barrier. Gral-Thala itself thus lies in a great pool of air surrounded by the ranges and the barrier. On the rest of the Moon, as here, air only remains in deep crevices and caverns like this."

"But these caves were a great labor in themselves..." Ripon began.

* * * * *

"Originally these caverns were built as outposts of Gral-Thala, built here because of their nearness to valuable mineral deposits. People came out from the sunlit cities within the Great Barrier to put in a tour of duty in the caverns. Again life on the Moon had reached a pleasant equilibrium. And then came the great disaster! Some two centuries ago a group of several hundred outlaws fleeing from Earth came here in a big space-ship."

"The _Mercury_!" Larry exclaimed.

"Exactly. Those men and women who came from Earth were few in comparison to the population of the Moon, but they were cruel and ruthless and they had weapons of war. The peaceful Lunarians had at that time no weapons at all, for they had no need for them. Within a few months the invaders made themselves Lords of all Gral-Thala! That was when English, the language of the invaders, came to be spoken by everybody on the Moon as well as the softer tongue of the Lunarians themselves. A few of the hardier folk in Gral-Thala fled to these caverns as outlaws. The invaders made only half-hearted attempts to come after them, and with the passing of the years the location of these refuges has been forgotten by people living within the Great Barrier. That is why these places are now known as the Lost Caverns."

"And the invaders still rule?"

"Their descendants are still Lords of Gral-Thala. Cruel and ruthless they always were, decadent and dissolute they have now become as well, but they still rule the sunny valley that was the pride of the ancient Lunarians. They hold the power, and they are aided by a few groups among the people of Gral-Thala who have sacrificed their honor to fawn upon their masters. Our spies, who penetrate beyond the barrier, tell us that before long there will come a day when the people are ready for revolt--but the time is not yet."

"But surely!" said Pyatt of Kagan, his deep voice breaking in on the low monotone in which Staunton had spoken, "surely our visitors will return to Earth, now that interplanetary travel has become possible, and bring us the warriors and equipment to storm the high palaces of the tyrants of Gral-Thala!"

"I should think that the Confederation of Earth would send help, particularly since the original invaders were outlaws from that planet," Staunton said. "How about it, friend Ripon? How are conditions back on Earth at this time?"

Ripon straightened up and shook his shoulders. The glow in his eyes faded away, and the lines in his face deepened once more.

"The Lunarians can look for no help from Earth until one thing is accomplished," he said. "I have been letting scientific enthusiasm make me lose sight of our reason for coming here. How are conditions on Earth, you ask? I can tell you in a single sentence. Unless we of Earth very quickly get a new supply of radium salts suitable for use with the Riesling Method, in a few weeks we all perish!"

"I do not understand."

In a few hasty phrases Ripon sketched the development of the terrible plague that was so swiftly robbing Earth of its inhabitants. At the end Staunton leaned back in his chair.

"Such salts are available on the Moon in ample quantity," he said slowly, and something in the quality of his voice robbed the words of the reassurance they would otherwise have held, "but--they are all located well within the area of the Great Barrier. And the Lords of Gral-Thala would never let you have even a single milligram!"

"Then there's only one thing to be done!" Larry stood up and began to peel off his space suit. "If someone will show me the way, I'll go into Gral-Thala and bring out as much of the radiatron extract as I can carry."

"And I will go with you!" boomed Pyatt of Kagan. "By Gorton and Laila, mythical gods of the Moon, it will take more than a few of those cold-eyed tyrants to stop us!"

XII

Time was the thing that counted. The remorseless pressure of minutes and hours that passed and could never be recalled! The tyrants who lorded it over Gral-Thala had no weapons more deadly than the electronic guns that had been common on Earth two hundred years before. A battalion of troops from Earth, wearing armor of dura-steel and carrying ray-guns, could probably have overthrown the Invaders very quickly. But--there was no time! The toll of the Gray Death was increasing with each passing hour, back there on the Good Green Planet, and the little group on the Moon would have to do what they could without hope of assistance.

They could not pause for proper preparations or careful planning. It was only half an Earth day after they had landed on the Moon, time enough to snatch a few hours' sleep, that Larry found himself moving up toward the surface in a slowly crawling cable car. Chotan already lay behind and far below them, and the oxygen indicator fastened to the sleeve of the space suit showed him that the air was thinning rapidly.

Colton and Pyatt were with him. All three of them wore space suits of the Lunarian patterns, that had a metal helmet with glass windows at the front and sides, for the difference in design of the space suits from the _Sky Maid_ would have made them too conspicuous. Pyatt had come along because he had often penetrated beyond the Great Barrier in disguise, and a second Lunarian was waiting for them up on the surface.

Ripon had also wanted to come, the idea of this daring raid setting the old, reckless light danging in his eyes. Finally he agreed that one of the leaders of the _Sky Maid_ expedition had better remain in the Caverns in case of disaster to the raiders.

"That's the hell of getting along in years, young feller!" he rumbled regretfully. "There's nothing I'd like better than to penetrate the barrier with you and pull the whiskers off the tyrants in their lair. A quick wit and a ready weapon! But I couldn't keep up with you younger men if the going gets hot--though I never thought the day would come when I'd hear Crispin Gillingwater Ripon admit a thing like that!--and you'd better go on without me."

"We'll be back soon," Larry said. Ripon snorted.

"If you're not back in five days I'm coming after you with the crew of the _Sky Maid_ and as many of the folk of the Caverns as I can get to come along!"

* * * * *

The Cavern of Chotan was in that part of the Moon which is sometimes in sunlight and sometimes in darkness, and it was night when they came out of the tunnel. The moisture on the space suit instantly froze into a fine white frost. A few Lunarian sentries waited for them there, and nearly a hundred of the Insect-men. With them were two carts that had high wheels and springs, something like an old-fashioned Earthly buckboard.

For a few moments, Pyatt talked to the leaders of the Insect-men in their clicking tongue. The glowing knobs atop their antennae bobbed up and down as they nodded their heads in understanding. Then Pyatt motioned Colton into one of the carts and climbed in beside him. Another Lunarian, slender even in the bulky space suit, climbed into the second cart beside Larry. Pyatt swung his right arm forward.

A score of the Insect-men instantly scampered ahead as scouts, spreading out like the spokes of a fan. Small parties went out to either flank. The rest, about thirty to each cart, gripped the trailing ropes and darted ahead with the wagons following behind them. They went at almost incredible speed, the four legs of each giving them a steady drive.

Even though the Insect-men were picking the smooth stretches of the rock and were evidently following a definite though unmarked trail, it was rough going. The light wagons jolted and banged as they whizzed along, and Larry had to cling to the rail with both hands to keep from being thrown off.

"Is all the way as rough as this?" he panted to his companion.

"Better soon," the Lunarian said shortly.

After about three hours they turned into a smooth and level road. It wound up and down over the rolling rocky plain, evidently a highway of great age. Occasionally they passed crumbling ruins beside it. Larry supposed that the road and the ruins dated back to those very ancient days before the Lunarians withdrew their shrinking supply of air within the Great Barrier.

Now that the road was smooth, the Insect-men pulled the carts along at a whizzing pace. The light wheels whirred as the wagons shot ahead. The scene, Larry reflected, was like a nightmare. All about him were the chill mountains and craters of the Moon, lifting their jagged peaks against the cold stars. Ahead of the speeding wagon ran the toiling cluster of Insect-men, their hard shells gleaming faintly in the starlight and their glowing antennae bobbing in a swift rhythm as they ran. The treads of the wheels rattled on the rocky surface of the road, the horny feet of the Insect-men made a steady scraping sound as they ran. The two men seated in the cart ahead were monstrous and misshapen figures in their space suits.

Larry's companion had remained sullenly silent, in spite of several efforts to start a conversation. This was unusual in one of the normally pleasant and talkative Lunarians, but Larry had not thought much about it. Now, as he made some remark about the speed of their progress, he heard a low chuckle and in his earphones sounded the voice of Diana Staunton.

"Yes, Larry, we travel fast. In a few days we will enter the zone of sunlight."

"_You_," he exclaimed. "This expedition is too dangerous. I would never have let you come if I had known."

"Why else do you think I kept so silent until now, when it is too late to send me back?" she asked, and though he could not see her face through the glass of her helmet in the darkness he could tell that she was smiling. "Neither would Pyatt of Kagan or my father have let me come. I stole the space suit of the young man who was to accompany you and left him locked in a storeroom."

"You will have to remain outside when we go within the barrier."

"Where you go, I go," she said with finality.

* * * * *

Sunrise on the Moon! There was no sudden onslaught of light as on the Earth, for the Moon day was twenty-eight days long! Yet, as they progressed steadily toward the horizon, the Moon's rotation brought the edge of the sun gradually into sight above the barren horizon, and as the days passed, a blinding glare of light swept in upon them and they moved the dark glasses into place in front of the windows of their space-suit helmets.

The temperature rose rapidly with the coming of the two weeks' sunlight, and before long the frost on the space suits was melting. Then, stretching along the crest of a mighty mountain range ahead, Larry saw a lofty gray wall that went so high its top was almost lost from view above. They had come within sight of the Great Barrier!

XIII

Several times along the way they had been halted by sentry-patrols from some of the other outlaw caverns, who warned them that an unusual number of strong parties of troops from Gral-Thala were roaming the waste-land. However, they came without incident to a tiny outlaw hide-out. This was within half a mile of one of the caverns that was under the domination of the Lords of Gral-Thala.

Two hours later Larry and the others stood with a score of other people, in an air-lock in a great tunnel that led through the mountain range and into Gral-Thala. All these people were residents of the valley returning from a tour of duty in the caverns, and the four outlaws from Chotan had been furnished with forged documents that gave them the same identity.

The space suits had been removed and hung on numbered racks. The three men wore the tight tunics and loose trousers that were the customary dress within the valley, as distinguished from the loin cloth and cloak of the cavern outlaws. This was fortunate, for the trousers concealed the sturdy Earthly legs of Larry and Colton which would have stood out in sharp contrast to the typical spindly shanks of the otherwise well-built Lunarians. Diana wore a loose robe, with tight wrappings concealing her hair and a thin veil over her face.

A heavy guard of soldiers checked the papers of all the travelers before they let them through. These troops wore light armor, and each carried an electronic gun slung from his shoulder. The officers were evidently of the Invaders, cruel-eyed men cast in the same mold as Xylon. The men were Lunarians, generally of a rather debased type and drawn from among the worst element in the population. A heavy-featured trooper glanced at Larry's papers in a perfunctory manner, then handed them back.

"All right, all right!" he growled. "Get along. Don't block the way!"

The tunnel ended on the inner slope of the mountain range surrounding Gral-Thala, where many cars ran down the steep incline into the city below. It was a pleasant and smiling land that Larry Gibson saw before him, a sunlit and fertile valley so vast that even the lofty range on the far side was invisible over the horizon. Towns and villages dotted the plain. Farms lay among their fertile fields. A small river wound through the center. Directly below him, clustered against this part of the valley wall, was a mighty city.

"This is the city of Pandonaria," Diana's voice came softly through her veil, "capital city of Gral-Thala."

The city itself was a terraced mass of colored buildings cut by many streets and interspersed with gardens. Several towering palaces of white and gold, the abodes of the Lords of Gral-Thala, dominated the lower buildings. It was good to see real sunlight again! To see birds flying overhead! To smell the odor of flowers and growing things, in contrast to the flat and motionless air of the Lost Caverns! It was hard to believe that this pleasant spot was really the scene of such a brutal tyranny as he had been told. Then they rounded a bend in the sloping road and came to an abrupt halt.

* * * * *

At the side of the road stood a sort of gallows, made of strips of a ruddy metal bolted together. From it hung the nude body of a young Lunarian girl. She was suspended by her bound wrists high above her head, and her feet swung far off the ground. From the clotted blood at her bound wrists, and the way the eternal sun of the valley had burned her skin, Larry knew that she had hung there many hours. The girl was far gone but she was not yet dead. At intervals her drooping head moved feebly from side to side. A pair of armored soldiers leaned on their weapons below the gallows. Around the girl's neck hung a sign, lettered in the archaic English script that was the official language of Gral-Thala:

"THIS GIRL DARED STRIKE ONE OF THE NOBLES OF GRAL-THALA WHO CONDESCENDED TO NOTICE HER."

Fierce anger filled Larry Gibson's heart, a consuming anger that set his clenched fists shaking. For some reason he thought of Diana. Though she stood only a few feet away from him, he visioned her hanging from such a gallows if the dissolute tyrants of this land ever stormed the Lost Caverns. Then Pyatt of Kagan laid a hand on his arm.

"Careful, my friend!" the Lunarian hissed. "Your anger shows on your face, and that is bad. We cannot help that poor girl now. Come!"

They went down into the city, avoiding the broad boulevards and keeping to the narrower streets where the poorer people were. As they passed by the base of one of the high palaces, they came to the body of a girl who lay crushed on the stones and had evidently been thrown or jumped from one of the upper windows. An aged man stood astride the body, leaning back and shaking his skinny fists at the white and gold bulk of the palace above him.

"Woe be upon the Lords of Gral-Thala!" he screamed in his shrill old voice. "Triple woe upon the tyrants and upon the decadent parasites who fawn upon them. Evil lies in wait for ye, lurking in your white palaces with your guards and your harlots! The hour of doom is not far away! The vengeance of Gorton and Laila may be long delayed, but it comes in the end! Woe to the Lords of Gral-Thala!"

An uneasy, sullen, murmuring crowd was gathered around the ragged old man although they left a broad circle of vacant space around him and the body of his granddaughter. A few troopers of the garrison were making a half-hearted effort to push the crowd back. They were uncomfortable in the face of the unspoken but obvious hatred of the throng. Larry and the others prudently kept to the back of the crowd. Even so, they were near enough to see what happened next.

Silver bells rang sharply, and lackeys called an arrogant summons to clear the way. In the midst of a circle of armed guards, porters carried a swaying gilt litter. On the cushions of the litter rested a man. It was one of the nobles of Gral-Thala, a perfumed degenerate in silken robes with a rouged and painted face. For a moment he stared at the crowds with his arrogantly scornful eyes. Then, as he saw the old man beside the girl's body and heard the curses he was shouting, his patrician face was distorted into a sneering frown.

The noble snarled an order, and one of his guards lifted his electronic rifle. There was a flash of blinding light! A sudden clap of miniature thunder, and a smell of ozone. The man-made lightning bolt struck the old man in the chest and knocked him sprawling across the body of his granddaughter. With a faint smile the noble leaned back on the cushions of the litter and waved languidly to his porters to move on again.

"Let us go, my friends!" Pyatt whispered hoarsely. "We cannot right all the wrongs of Gral-Thala at one stroke, and our mission is the most important thing at the moment."

XIV

They were walking slowly down one of the quiet streets of the city, a quarter where there were few guards and little chance of discovery. Larry noticed that all the windows were equipped with heavy shutters, so that the light could be closed out when the inhabitants of this land desired to sleep. It was a place of unending daylight, always turned toward the sun, where darkness never came. Colton was more interested in the metal rails that ran along the walks on the outside of the buildings.

"My Lord!" he said softly, "These are gold!"

"Of course," Pyatt of Kagan said absently, "Gold is one of the most common metals in Gral-Thala. Our problem is the matter of the radium salts. I happen to know that they are stored in small boxes made of ura-lead, in one of the government storehouses. It would be easier to steal some direct from the mines, but there is no time for that because of the question of proper packing and handling. We must risk everything on a bold attempt to raid the warehouses."

"Suits me," Larry said quietly. Just then Diana gripped him by the arm and jerked him back against the wall of the nearest building.

"Look there!" she hissed.

Another litter was passing along the cross street just ahead of them. This litter went in evident haste, with lackeys swinging whips to clear the path and the passenger bending forward to urge his bearers to greater haste. The man who rode in the litter was Xylon!

The four outlaws stared at each other in grim and ominous surprise. There had been no doubt of the identity of the man who had just passed within a few yards of them.

"But what does _that_ mean?" Larry gasped.

"It means that I have been a fool!" Pyatt snarled. "Xylon is evidently no outlaw who came to the caverns to seek shelter, but a spy sent out by the Lords of Gral-Thala. Now I understand the reason for that revolt among the Insect-men! He must have stirred it up in an attempt to kidnap Diana here because of her hold over those simple creatures. Now the location of the Lost Caverns is at last known to the tyrants, and there will be an attack in force."

"And Xylon knows that we are here in Pandonaria!" Diana exclaimed.

"Which means that all our lives hang by a thread no heavier than a woman's hair! We must get under cover at once! Then we will send word back to the Caverns by secret radio, that they may prepare for an assault. After that we will plan an attempt on the radium salts."

The outlaws of the Lost Caverns had certain confederates within the city, and they now took refuge in the house of a small merchant who was a distant cousin of Pyatt. Larry watched as Pyatt and the merchant crouched over the sending set concealed in a small closet built in the thickness of one of the walls, the arkon-bulbs flashing as they sent the warning to Chotan to be spread to the other caverns. At last Pyatt straightened up.

"At least that is done," he said. "Now we will wait two hours, which will be the time of the Third Meal. There will be few people on the streets, and the warehouse guards will be drowsy, and we will have our best chance."

* * * * *

Pyatt and Colton had gone somewhere else in the house, and Larry sat with Diana in a small room whose windows looked out on the green fields beyond the city. The girl had loosened her blue veil so that it hung in soft folds about her chin.

"This is the first time in my life I have been anywhere but in the Caverns and on the waste-land," she said moodily. "This valley of Gral-Thala is a pleasant place."

"You would like Earth even better."

"I suppose I would. Will you take me back to that Earth of yours when you return, Larry?"

"Not until the Gray Death is overcome! I would not want to take any chance of it striking you down."

"Do you love me, Larry?" she asked, without either coquetry or embarrassment.

"I guess I do. Of course, we've only known each other for a few hours--but I guess I do."

"I am glad," she said simply.

The two hours passed, and Pyatt came striding back into the room. They had given him one of the ray-guns brought ashore from the _Sky Maid_, and he carried it thrust in his girdle close to his hand.

"It is time to go," he said. "We must make our attempt now, win or lose. Where is Colton?"

"I thought he was with you."

"Haven't seen him in two hours!"

A hasty search of the merchant's house and small grounds revealed no trace of the missing officer. Pyatt stood glowering blackly and pulling at his chin.

"I don't like it," he said. "Yet, if the soldiers had taken him, they would have come for us as well."

A different thought was running through Larry's mind, a grim and unpleasant suspicion. He was remembering Colton's past history ... his general sullenness ... the greed that he had shown throughout the entire expedition. He was also remembering that he had seen Colton in deep conversation with Xylon a few hours before they had left Chotan.

"I am afraid," he said bitterly, "that Colton has sold us out to Xylon and the Lords of Gral-Thala for promise of reward. We had better get out of this house right away, before...."