Only two young explorers stand in the way of the mad Bram's horrible revenge-the releasing of his trillions of man-sized beetles upon an utterly defenseless world. Out of the south the biplane came winging back toward the camp, a black speck against the dazzling white of the vast ice-fields that extended unbroken to the horizon on every side.

It came out of the south, and yet, a hundred miles further back along the course on which it flew, it could not have proceeded in any direction except northward. For a hundred miles south lay the south pole, the goal toward which the Travers Expeditions had been pressing for the better part of that year.

Not that they could not have reached it sooner. As a matter of fact, the pole had been crossed and re-crossed, according to the estimate of Tommy Travers, aviator, and nephew of the old millionaire who stood fairy uncle to the expedition. But one of the things that was being sought was the exact site of the pole. Not within a couple of miles or so, but within the fraction of an inch.

It had something to do with Einstein, and something to do with terrestrial magnetism, and the variations of the south magnetic pole, and the reason therefore, and something to do with parallaxes and the precession of the equinoxes and other things, this search for the pole's exact location. But all that was principally the affair of the astronomer of the party. Tommy Travers, who was now evidently on his way back, didn't give a whoop for Einstein, or any of the rest of the stuff. He had been enjoying himself after his fashion during a year of frostbites and hard rations, and he was beginning to anticipate the delights of the return to Broadway.

Captain Storm, in charge of the expedition, together with the five others of the advance camp, watched the plane maneuver up to the tents. She came down neatly on the smooth snow, skidded on her runners like an expert skater, and came to a stop almost immediately in front of the marquee.

Tommy Travers leaped out of the enclosed cockpit, which, shut off by glass from the cabin, was something like the front seat of a limousine. "Well, Captain, we followed that break for a hundred miles, and there's no ground cleft, as you expected," he said. "But Jim Dodd and I picked up something, and Jim seems to have gone crazy."

Through the windows of the cabin, Jim Dodd, the young archaeologist of the party, could be seen apparently wrestling with something that looked like a suit of armor. By the time Captain Storm, Jimmy, and the other members of the party had reached the cabin door, Dodd had got it open and flung himself out backward, still hugging what he had found, and maneuvering so that he managed to fall on his back and sustain its weight.

"Say, what the-what-what's that?" gasped Storm. Even the least scientific minded of the party gasped in amazement at what Dodd had. It resembled nothing so much as an enormous beetle. As a matter of fact, it was an insect, for it had the three sections that characterize this class, but it was merely the shell of one. Between four and five feet in height, when Dodd stood it on end, it could now be seen to consist of the hard exterior substance of some huge, unknown coleopter.

This substance, which was fully three inches thick over the thorax, looked as hard as plate armor. "What is it?" gasped Storm again. Tommy Travers made answer, for James Dodd was evidently incapable of speech, more from emotion than from the force with which he had landed backward in the snow.

"We found it at the pole, Captain," he said. "At least, pretty near where the pole ought to be. We ran into a current of warm air or something. The snow had melted in places, and there were patches of bare rock. This thing was lying in a hollow among them." "If I didn't see it before my eyes, I'd think you crazy, Tommy," said Storm with some asperity. "What is it, a crab?"

"Crab be damned!" shouted Jim Dodd, suddenly recovering his faculties. "My God, Captain Storm, don't you know the difference between an insect and a crustacean? This is a fossil beetle. Don't you see the distinguishing mark of the coleoptera, those two elytra, or wing-covers, which meet in the median dorsal line? A beetle, but with the shell of a crustacean instead of mere chitin. That's what led you astray, I expect. God, what a tale we'll have to tell when we get back to New York! We'll drop everything else, and spend years, if need be, looking for other specimens."

"Like fun you will!" shouted Higby, the astronomer of the party. "Lemme tell you right here, Dodd, nobody outside the Museum of Natural History is going to care a damn about your old fossils. What we're going to do is to march straight to the true pole, and spend a year taking observations and parallaxes. If Einstein's brochure, in which he links up gravitation with magnetism, is correct-"

"Fossil beetles!" Jim Dodd burst out, ignoring the astronomer. "That means that in the Tertiary Era, probably, there existed forms of life in the antarctic continent that have never been found elsewhere. Imagine a world in which the insect reached a size proportionate to the great saurians, Captain Storm! I'll wager poor Bram discovered this. That's why he stayed behind when the Greystoke Expedition came within a hundred miles of the pole. I'll wager he's left a cairn somewhere with full details inside it. We've got to find it. We-"

But Jim Dodd, suddenly realizing that the rest of the party could hardly be said to share his enthusiasm in any marked degree, broke off and looked sulky. "You say you found this thing pretty nearly upon the site of the true pole?" Captain Storm asked Tommy. "Within five miles, I'd say, Captain. The fog was so bad that we couldn't get our directions very well."

"Well, then, there's going to be no difficulty," answered Storm. "If this fair weather lasts, we'll be at the pole in another week, and we'll start making our permanent camp. Plenty of opportunity for all you gentlemen. As for me, I'm merely a sailor, and I'm trying to be impartial.

"And please remember, gentlemen, that we're well into March now, and likely to have the first storms of autumn on us any day. So let's drop the argument and remember that we've got to pull together!" Tommy Travers was the only skilled aviator of the expedition, which had brought two planes with it. It was a queer friendship that had sprung up between him and Jim Dodd. Tommy, the blasé ex-Harvard man, who was known along Broadway, and had never been able to settle down, seemed as different as possible from the spectacled, scholarly Dodd, ten years his senior, red-haired, irascible, and living, as Tommy put it, in the Age of Old Red Sandstone, instead of in the year 1930 A. D.

It was generally known-though the story had been officially denied-that there had been trouble in the Greystoke Expedition of three years before. Captain Greystoke had taken the brilliant, erratic Bram, of the Carnegie Archaeological Institute, with him, and Bram's history was a long record of trouble.

It was Bram who had exploded the faked neolithic finds at Mannheim, thereby earning the undying enmity of certain European savants, but brilliantly demolishing them when he smashed the so-called Mannheim stone pitcher (valued at a hundred thousand dollars) with a pocket-axe, and caustically inquired whether neolithic man used babbit metal rivets to fasten on his jug handles.

Bram's brilliant work in the investigation of the origin of the negrito Asiatic races had been awarded one of the Nobel prizes, and Bram had declined it in an insulting letter because he disapproved of the year's prize award for literature.

He had been a storm center for years, embittered by long opposition, when he joined the Greystoke Expedition for the purpose of investigating the marine fauna of the antarctic continent. And it was known that his presence had nearly brought the Greystoke Expedition to the point of civil war. Rumor said he had been deliberately abandoned. His enemies hoped he had. The facts seemed to be, however, that in an outburst of temper he had walked out of camp in a furious snowstorm and perished. For days his body had been sought in vain.

Jimmy Dodd had run foul of Bram some years before, when Bram had published a criticism of one of Dodd's addresses dealing with fossil monotremes, or egg-laying mammals. In his inimitable way, Bram had suggested that the problem which came first, the egg or the chicken, was now seen to be linked up with the Darwinian theory, and solved in the person of Dodd.

Nevertheless, Jimmy Dodd entertained a devoted admiration for the memory of the dead scientist. He believed that Bram must have left records of inestimable importance in a cairn before he died. He wanted to find that cairn.

And he knew, what a number of Bram's enemies knew, that the dead scientist had been a morphine addict. He believed that he had wandered out into the snow under the influence of the drug. Dodd, who shared a tent with Tommy, had raved the greater part of the night about the find.

"Well, but see here, Jimmy, suppose these beetles did inhabit the antarctic continent a few million years ago, why get excited?" Tommy had asked. "Excited?" bellowed Dodd. "It opens one of the biggest problems that science has to face. Why haven't they survived into historic times? Why didn't they cross into Australia, like the opossum, by the land bridge then existent between that continent and South America? Beetles five feet in length, and practically invulnerable! What killed them off? Why didn't they win the supremacy over man?"

Jimmy Dodd had muttered till he went to sleep, and he had muttered worse in his dreams. Tommy was glad that Captain Storm had given them permission to return to the same spot next morning and look for further fossils, though his own interest in them was of the slightest.

The dogs were being harnessed next morning when the two men hopped into the plane. The thermometer was unusually high for the season, for in the south polar regions the short summer is usually at an end by March. Tommy was sweating in his furs in a temperature well above the freezing point. The snow was crusted hard, the sky overcast with clouds, and a wind was blowing hard out of the south, and increasing in velocity hourly.

"A bad day for starting," said Captain Storm. "Looks like one of the autumn storms was blowing up. If I were you, I'd watch the weather, Tommy." Tommy glanced at Dodd, who was huddled in the rear cockpit, fuming at the delay, and grinned whimsically. "I guess I can handle her, Captain," he answered. "It's only an hour's flight to where he found that fossil."

"Just as you please," said Storm curtly. He knew that Tommy's judgment as a pilot could always be relied upon. "You'll find us here when you return," he added. "I've counter-manded the order to march. I don't like the look of the weather at all."

Tommy grinned again and pressed the starter. The engine caught and warmed up. One of the men kicked away the blocks of ice that had been placed under the skids to serve as chocks. The plane taxied over the crusted snow, and took off into the south.

The camp was situated in a hollow among the ice-mountains that rose to a height of two or three thousand feet all around. Tommy had not dreamed how strongly the gale was blowing until he was over the top of them. Then he realized that he was facing a tougher proposition than he had calculated on. The storm struck the biplane with full force.

A snowstorm was driving up rapidly, blackening the sky. The sun, which only appeared for a brief interval every day, was practically touching the horizon as it rose to make its minute arc in the sky. A star was visible through a rift in the clouds overhead, and the pale daylight in which they had started had already become twilight.

Tommy was tempted to turn back, but it was only a hundred miles, and Jimmy Dodd would give him no peace if he did so. So he put the plane's nose resolutely into the wind, watching his speed indicator drop from a hundred miles per hour to eighty, sixty, forty-less.

The storm was beating up furiously. Of a sudden the clouds broke into a deluge of whirling snow. In a moment the windshield was a frozen, opaque mass. Tommy opened it, and peered out into the biting air. He could see nothing.... The plane, caught in the fearful cross-currents that swirl about the southern roof of the world, was fluttering like a leaf in the wind. The altimeter was dropping dangerously.

Tommy opened the throttle to the limit, zooming, and, like a spurred horse, the biplane shot forward and upward. She touched five thousand, six, seven-and that, for her, was ceiling under those conditions, for a sudden tremendous shock of wind, coming in a fierce cross-current, swung her round, tossed her to and fro in the enveloping white cloud. And Tommy knew that he had the fight of his life upon his hands.

The compasses, which required considerable daily adjusting to be of use so near to the pole, had now gone out of use altogether. The air speed indicator had apparently gone west, for it was oscillating between zero and twenty. The turn and bank indicator was performing a kind of tango round the dial. Even the eight-day clock had ceased to function, but that might have been due to the fact that Tommy had neglected to wind it. And the oil pressure gauge presented a still more startling sight, for a glance showed that either there was a leak or else the oil had frozen.

Tommy looked around at Dodd and pointed downward. Dodd responded with a vicious forward wave of his hand. Tommy shook his head, and Dodd started forward along the cabin, apparently with the intention of committing assault and battery upon him. Instead, the archaeologist collapsed upon the floor as the plane spun completely around under the impact of a blast that was like a giant's slap.

The plane was no longer controllable. True, she responded in some sort to the controls, but all Tommy was able to do was to keep her from going into a crazy sideslip or nose dive as he fought with the elements. And those elements were like a devil unchained. One moment he was dropping like a plummet, the next he was shooting up like a rocket as a vertical blast of air caught the plane and tossed her like a cork into the invisible heavens. Then she was revolving, as if in a maelstrom, and by degrees this rotary movement began to predominate.

Round and round went the plane, in circles that gradually narrowed, and it was all Tommy could do to swing the stick so as to keep her from skidding or sideslipping. And as he worked desperately at his task Tommy began to realize something that made him wonder if he was not dreaming.

The snow was no longer snow, but rain-mist, rather, warm mist that had already cleared the windshield and covered it with tiny drops. And that white, opaque world into which he was looking was no longer snow but fog-the densest fog that Tommy had ever encountered.

Fog like white wool, drifting past him in fleecy flakes that looked as if they had solid substance. Warm fog that was like balm upon his frozen skin, but of a warmth that was impossible within a few miles of the frozen pole.

Then there came a momentary break in it, and Tommy looked down and uttered a cry of fear. Fear, because he knew that he must be dreaming. Not more than a thousand feet beneath him he saw patches of snow, and patches of-green grass, the brightest and most verdant green that he had ever seen in his life.

He turned round at a touch on his shoulder. Dodd was leaning over him, one hand pointing menacingly upward and onward. "You fool," Tommy bellowed in his ear, "d'you think the south pole lies over there? It's here! Yeah, don't you get it, Jimmy? Look down! This valley-God, Jimmy, the south pole's a hole in the ground!"

And as he spoke he remembered vaguely some crank who had once insisted that the two poles were hollow because-what was the fellow's reasoning? Tommy could not remember it.

But there was no longer any doubt but that they were dropping into a hole. Not more than a mile around, which explained why neither Scott nor Amundsen had found it when they approximated to the site of the pole. A hole-a warm hole, up which a current of warm air was rushing, forming the white mist that now gradually thinned as the plane descended. The plateau with its covering of eternal snows loomed in a white circle high overhead. Underneath was green grass now-grass and trees!

The fog was nearly gone. The plane responded to the controls again. Tommy pushed the stick forward and came round in a tighter circle. And then something happened that he had not in the least expected. One moment he seemed to be traveling in a complete calm, a sort of clear funnel with a ring of swirling fog outside it-the next he was dropping into a void!

There was no air resistance-there seemed hardly any air, for he felt a choking in his throat, and a tearing at his lungs as he strove to breathe. He heard a strangled cry from Dodd, and saw that he was clutching with both hands at his throat, and his face was turning purple.

The controls went limp in Tommy's hands. The plane, gyrating more slowly, suddenly nosed down, hung for a moment in that void, and then plunged toward the green earth, two hundred feet below, with appalling swiftness.

Tommy realized that a crash was inevitable. He threw his goggles up over his forehead, turned and waved to Dodd in ironic farewell. He saw the earth rush up at him-then came the shattering crash, and then oblivion!