There was no use hiding from the truth. Somebody had blundered--a fatal blunder--and they were going to pay for it! Mark Forepaugh kicked the pile of hydrogen cylinders. Only a moment ago he had broken the seals--the mendacious seals that certified to the world that the flasks were fully charged. And the flasks were empty! The supply of this precious power gas, which in an emergency should have been sufficient for six years, simply did not exist.

He walked over to the integrating machine, which as early as the year 2031 had begun to replace the older atomic processes, due to the shortage of the radium series metals. It was bulky and heavy compared to the atomic disintegrators, but it was much more economical and very dependable. Dependable--provided some thick-headed stock clerk at a terrestrial supply station did not check in empty hydrogen cylinders instead of full ones. Forepaugh’s unwonted curses brought a smile to the stupid, good-natured face of his servant, Gunga--he who had been banished for life from his native Mars for his impiety in closing his single round eye during the sacred Ceremony of the Wells.

The Earth man was at this steaming hot, unhealthful trading station under the very shadow of the South Pole of the minor planet Inra for an entirely different reason. One of the most popular of his set on the Earth, an athletic hero, he had fallen in love, and the devoutly wished-for marriage was only prevented by lack of funds. The opportunity to take charge of this richly paid, though dangerous, outpost of civilization had been no sooner offered than taken. In another week or two the relief ship was due to take him and his valuable collection of exotic Inranian orchids back to the Earth, back to a fat bonus, Constance, and an assured future.

It was a different young man who now stood tragically before the useless power plant. His slim body was bowed, and his clean features were drawn. Grimly he raked the cooling dust that had been forced in the integrating chamber by the electronic rearrangement of the original hydrogen atoms--finely powdered iron and silicon--the “ashes” of the last tank of hydrogen.

Gunga chuckled.

“What’s the matter?” Forepaugh barked. “Going crazy already?”

“Me, haw! Me, haw! Me thinkin’,” Gunga rumbled. “Haw! We got, haw! plenty hydr’gen.” He pointed to the low metal roof of the trading station. Though it was well insulated against sound, the place continually vibrated to the low murmur of the Inranian rains that fell interminably through the perpetual polar day. It was a rain such as is never seen on Earth, even in the tropics. It came in drops as large as a man’s fist. It came in streams. It came in large, shattering masses that broke before they fell and filled the air with spray. There was little wind, but the steady green downpour of water and the brilliant continuous flashing of lightning shamed the dull soggy twilight produced by the large, hot, but hidden sun.

“Your idea of a joke!” Forepaugh growled in disgust. He understood what Gunga’s grim pleasantry referred to. There was indeed an incalculable quantity of hydrogen at hand. If some means could be found to separate the hydrogen atoms from the oxygen in the world of water around them they would not lack for fuel. He thought of electrolysis, and relaxed with a sigh. There was no power. The generators were dead, the air drier and cooler had ceased its rhythmic pulsing nearly an hour ago. Their lights were gone, and the automatic radio utterly useless.

“This is what comes of putting all your eggs in one basket,” he thought, and let his mind dwell vindictively on the engineers who had designed the equipment on which his life depended.

An exclamation from Gunga startled him. The Martian was pointing to the ventilator opening, the only part of this strange building that was not hermetically sealed against the hostile life of Inra. A dark rim had appeared at its margin, a loathsome, black-green rim that was moving, spreading out. It crept over the metal walls like the low-lying smoke of a fire, yet it was a solid. From it emanated a strong, miasmatic odor.

“The giant mold!” Forepaugh cried. He rushed to his desk and took out his flash pistol, quickly set the localizer so as to cover a large area. When he turned he saw, to his horror, Gunga about to smash into the mold with his ax. He sent the man spinning with a blow to the ear.

“Want to scatter it and start it growing in a half-dozen places?” he snapped. “Here!”

He pulled the trigger. There was a light, spiteful “ping” and for an instant a cone of white light stood out in the dim room like a solid thing. Then it was gone, and with it was gone the black mold, leaving a circular area of blistered paint on the wall and an acrid odor in the air. Forepaugh leaped to the ventilating louver and closed it tightly.

“It’s going to be like this from now on,” he remarked to the shaken Gunga. “All these things wouldn’t bother us as long as the machinery kept the building dry and cool. They couldn’t live in here. But it’s getting damp and hot. Look at the moisture condensing on the ceiling!”

Gunga gave a guttural cry of despair. “It knows, Boss; look!”

Through one of the round, heavily framed ports it could be seen, the lower part of its large, shapeless body half-floating in the lashing water that covered their rocky shelf to a depth of several feet, the upper part spectral and gray. It was a giant amoeba, fully six feet in diameter in its present spheroid form, but capable of assuming any shape that would be useful. It had an envelope of tough, transparent matter, and was filled with a fluid that was now cloudy and then clear. Near the center there was a mass of darker matter, and this was undoubtedly the seat of its intelligence.

The Earth man recoiled in horror! A single cell with a brain! It was unthinkable. It was a biological nightmare. Never before had he seen one--had, in fact, dismissed the stories of the Inranian natives as a bit of primitive superstition, had laughed at these gentle, stupid amphibians with whom he traded when they, in their imperfect language, tried to tell him of it.

They had called it the Ul-lul. Well, let it be so. It was an amoeba, and it was watching him. It floated in the downpour and watched him. With what? It had no eyes. No matter, it was watching him. And then it suddenly flowed outward until it became a disc rocking on the waves. Again its fluid form changed, and by a series of elongations and contractions it flowed through the water at an incredible speed. It came straight for the window, struck the thick, unbreakable glass with a shock that could be felt by the men inside. It flowed over the glass and over the building. It was trying to eat them, building and all! The part of its body over the port became so thin that it was almost invisible. At last, its absolute limit reached, it dropped away, baffled, vanishing amid the glare of the lightning and the frothing waters like the shadows of a nightmare.

The heat was intolerable and the air was bad.

“Haw, we have to open vent’lator, Boss!” gasped the Martian.

Forepaugh nodded grimly. It wouldn’t do to smother either. Though to open the ventilator would be to invite another invasion by the black mold, not to mention the amoebae and other fabulous monsters that had up to now been kept at a safe distance by the repeller zone, a simple adaptation of a very old discovery. A zone of mechanical vibrations, of a frequency of 500,000 cycles per second, was created by a large quartz crystal in the water, which was electrically operated. Without power, the protective zone had vanished.

“We watch?” asked Gunga.

“You bet we watch. Every minute of the ‘day’ and ‘night.’”

He examined the two chronometers, assuring himself that they were well wound, and congratulated himself that they were not dependent on the defunct power plant for energy. They were his only means of measuring the passage of time. The sun, which theoretically would seem to travel round and round the horizon, rarely succeeded in making its exact location known, but appeared to shift strangely from side to side at the whim of the fog and water.

“Th’ fellas,” Gunga remarked, coming out of a study. “Why not come?” He referred to the Inranians.

“Probably know something’s wrong. They can tell the quartz oscillator is stopped. Afraid of the Ul-lul, I suppose.”

“‘Squeer,” demurred the Martian. “Ul-lul not bother fellas.”

“You mean it doesn’t follow them into the underbrush. But it would find tough going there. Not enough water; trees there, four hundred feet high with thorny roots and rough bark--they wouldn’t like that. Oh no, these natives ought to be pretty snug in their dens. Why, they’re as hard to catch as a muskrat! Don’t know what a muskrat is, huh? Well, it’s the same as the Inranians, only different, and not so ugly.”

For the next six days they existed in their straitened quarters, one guarding while the other slept, but such alarms as they experienced were of a minor nature, easily disposed of by their flash pistol. It had not been intended for continuous service, and under the frequent drains it showed an alarming loss of power. Forepaugh repeatedly warned Gunga to be more sparing in its use, but that worthy persisted in his practice of using it against every trifling invasion of the poisonous Inranian cave moss that threatened them, or the warm, soggy water-spiders that hopefully explored the ventilator shaft in search of living food.

“Bash ‘em with a broom, or something! Never mind if it isn’t nice. Save our flash gun for something bigger.”

Gunga only looked distressed.

On the seventh day their position became untenable. Some kind of sea creature, hidden under the ever-replenished storm waters, had found the concrete emplacements of their trading post to its liking. Just how it was done was never learned. It is doubtful that the creatures could gnaw away the solid stone--more likely the process was chemical, but none the less it was effective. The foundations crumbled; the metal shell subsided, rolled half over so that silty water leaked in through the straining seams, and threatened at any moment to be buffeted and urged away on the surface of the flood toward that distant vast sea which covers nine-tenths of the area of Inra.

“Time to mush for the mountains,” Forepaugh decided.

Gunga grinned. The Mountains of Perdition were, to his point of view, the only part of Inra even remotely inhabitable. They were sometimes fairly cool, and though perpetually pelted with rain, blazing with lightning and reverberating with thunder, they had caves that were fairly dry and too cool for the black mold. Sometimes, under favorable circumstances on their rugged peaks, one could get the full benefit of the enormous hot sun for whose actinic rays the Martian’s starved system yearned.

“Better pack a few cans of the food tablets,” the white man ordered. “Take a couple of waterproof sleeping bags for us, and a few hundred fire pellets. You can have the flash pistol; it may have a few more charges in it.”

Forepaugh broke the glass case marked “Emergency Only” and removed two more flash pistols. Well he knew that he would need them after passing beyond the trading area--perhaps sooner. His eyes fell on his personal chest, and he opened it for a brief examination. None of the contents seemed of any value, and he was about to pass when he dragged out a long, heavy, .45 caliber six-shooter in a holster, and a cartridge belt filled with shells. The Martian stared.

“Know what it is?” his master asked, handing him the weapon.

“Gunga not know.” He took it and examined it curiously. It was a fine museum piece in an excellent state of preservation, the metal overlaid with the patina of age, but free from rust and corrosion.

“It’s a weapon of the Ancients,” Forepaugh explained. “It was a sort of family heirloom and is over 300 years old. One of my grandfathers used it in the famous Northwest Mounted Police. Wonder if it’ll still shoot.”

He leveled the weapon at a fat, sightless wriggler that came squirming through a seam, squinting unaccustomed eyes along the barrel. There was a violent explosion, and the wriggler disappeared in a smear of dirty green. Gunga nearly fell over backward in fright, and even Forepaugh was shaken. He was surprised that the ancient cartridge had exploded at all, though he knew powder making had reached a high level of perfection before explosive chemical weapons had yielded to the newer, lighter, and infinitely more powerful ray weapons. The gun would impede their progress. It would be of very little use against the giant Carnivora of Inra. Yet something--perhaps a sentimental attachment, perhaps what his ancestors would have called a “hunch”--compelled him to strap it around his waist. He carefully packed a few essentials in his knapsack, together with one chronometer and a tiny gyroscopic compass. So equipped, they could travel with a fair degree of precision toward the mountains some hundred miles on the other side of a steaming forest, a-crawl with feral life, and hot with blood-lust.

Man and master descended into the warm waters and, without a backward glance, left the trading post to its fate. There was not even any use in leaving a note. Their relief ship, soon due, would never find the station without radio direction.

The current was strong, but the water gradually became shallower as they ascended the sloping rock. After half an hour they saw ahead of them the loom of the forest, and with some trepidation they entered the gloom cast by the towering, fernlike trees, whose tops disappeared in murky fog. Tangled vines impeded their progress. Quagmires lay in wait for them, and tough weeds tripped them, sometimes throwing one or another into the mud among squirming small reptiles that lashed at them with spiked, poisonous feet and then fell to pieces, each piece to lie in the bubbling ooze until it grew again into a whole animal.

Several times they almost walked under the bodies of great, spheroidal creatures with massive short legs, whose tremendously long, sinuous necks disappeared in the leafy murk above, swaying gently like long-stalked lilies in a terrestial pond. These were azornacks, mild-tempered vegetarians whose only defense lay in their thick, blubbery hides. Filled with parasites, stinking and rancid, their decaying covering of fat effectively concealed the tender flesh underneath, protecting them from fangs and rending claws.

Deeper in the forest the battering of the rain was mitigated. Giant neo-palm leaves formed a roof that shut out not only most of the weak daylight, but also the fury of the downpour. The water collected in cataracts, ran down the boles of the trees, and roared through the semi-circular canals of the snake trees, so named by early explorers for their waving, rubbery tentacles, multiplied a millionfold, that performed the duties of leaves. Water gurgled and chuckled everywhere, spread in vast dim ponds and lakes writhing with tormented roots, up-heaved by unseen, uncatalogued leviathans, rippled by translucent discs of loathsome, luminescent jelly that quivered from place to place in pursuit of microscopic prey.

Yet the impression was one of calm and quiet, and the waifs from other worlds felt a surcease of nervous tension. Unconsciously they relaxed. Taking their bearings, they changed their course slightly for the nesting place of the nearest tribe of Inranians where they hoped to get food and at least partial shelter; for their food tablets had mysteriously turned to an unpleasant viscous liquid, and their sleeping bags were alive with giant bacteria easily visible to the eye.

They were doomed to disappointment. After nearly twelve hours of desperate struggling through the morass, through gloomy aisles, and countless narrow escapes from prowling beasts of prey in which only the speed and tremendous power of their flash pistols saved them from instant death, they reached a rocky outcropping which led to the comparatively dry rise of land on which a tribe of Inranians made its home. Their faces were covered with welts made by the hanging filaments of blood-sucking trees as fine as spider webs, and their senses reeled with the oppressive stench of the abysmal jungle. If the pampered ladies of the Inner Planets only knew where their thousand-dollar orchids sprang from!

Converging runways showed the opening of one of the underground dens, almost hidden from view by a bewildering maze of roots, rendered more formidable by long, sharp stakes made from the iron-hard thigh-bones of the flying kabo.

Forepaugh cupped his hands over his mouth and gave the call.

“Ouf! Ouf! Ouf! Ouf! Ouf!”

He repeated it over and over, the jungle giving back his voice in a muffled echo, while Gunga held a spare flash pistol and kept a sharp lookout for a carnivore intent on getting an unwary Inranian.

There was no answer. These timid creatures, who are often rated the most intelligent life native to primitive Inra, had sensed disaster and had fled.

Forepaugh and Gunga slept in one of the foul, poorly ventilated dens, ate of the hard, woody tubers that had not been worth taking along, and wished they had a certain stock clerk at that place at that time. They were awakened out of deep slumber by the threshing of an evil looking creature which had become entangled among the sharpened spikes. Its tremendous maw, splitting it almost in half, was opened in roars of pain that showed great yellow fangs eight inches in length. Its heavy flippers battered the stout roots and lacerated themselves in the beast’s insensate rage. It was quickly dispatched with a flash pistol and Gunga cooked himself some of the meat, using a fire pellet; but despite his hunger Forepaugh did not dare eat any of it, knowing that this species, strange to him, might easily be one of the many on Inra that are poisonous to terrestials.

They resumed their march toward the distant invisible mountains, and were fortunate in finding somewhat better footing than they had on their previous march. They covered about 25 miles on that “day,” without untoward incident. Their ray pistols gave them an insuperable advantage over the largest and most ferocious beasts they could expect to meet, so that they became more and more confident, despite the knowledge that they were rapidly using up the energy stored in their weapons. The first one had long ago been discarded, and the charge indicators of the other two were approaching zero at a disquieting rate. Forepaugh took them both, and from that time on he was careful never to waste a discharge except in case of a direct and unavoidable attack. This often entailed long waits or stealthy detours through sucking mud, and came near to ending both their lives.