The sun was a harsh ball of heat baking the ground and then, in some odd manner, drawing back that same fieriness. In the coolness of the eastern mountains Shann would not have believed that Warlock could hold such heat. The men discarded their jackets early as they swung to dip the poles. But they dared not strip off the rest of their clothing lest their skin burn. And again gusts of wind now drove sand over the edge of the cut to blanket the water.

Shann wiped his eyes, pausing in his eternal push-push, to look at the rocks which they were passing in threatening proximity. For the slash which held the river had narrowed. And the rock of its walls was naked of earth, save for sheltered pockets holding the drift of sand dust, while boulders of all sizes cut into the path of the flowing water.

He had not been mistaken; they were going faster, faster even than their efforts with the poles would account for. With the narrowing of the bed of the stream, the current was taking on a new swiftness. Shann said as much and Thorvald nodded.

"We're approaching the first of the rapids."

"Where we get off and walk around," Shann croaked wearily. The dust gritted between his teeth, irritated his eyes. "Do we stay beside the river?"

"As long as we can," Thorvald replied somberly. "We have no way of transporting water."

Yes, a man could live on very slim rations of food, continue to beat his way over a bad trail if he had the concentrate tablets they carried. But there was no going without water, and in this heat such an effort would finish them quickly. Always they both listened for another cry from behind, a cry to tell them just how near the Throg hunting party had come.

"No Throg flyers yet," Shann observed. He had expected one of those black plates to come cruising the moment the hound had pointed the direction for their pursuers.

"Not in a storm such as this." Thorvald, without releasing his hold on the raft pole, pointed with his chin to the swirling haze cloaking the air above the cut walls. Here the river dug yet deeper into the beginning of a canyon. They could breathe better. The dust still sifted down but not as thickly as a half hour earlier. Though over their heads the sky was now a grayish lid, shutting out the sun, bringing a portion of coolness to the travelers.

The Survey officer glanced from side to side, watching the banks as if hunting for some special mark or sign. At last he used his pole as a pointer to indicate a rough pile of boulders ahead. Some former landslide had quarter dammed the river at that point, and the drift of seasonal floods was caught in and among the rocky pile to form a prickly peninsula.

"In there——"

They brought the raft to shore, fighting the faster current. The wolverines, who had been subdued by the heat and the dust, flung themselves to the rocks with the eagerness of passengers deserting a sinking ship for certain rescue. Thorvald settled the map case more securely between his arm and side before he took the same leap. When they were all ashore he prodded the raft out into the stream again, pushing the platform along until it was sucked by the current past the line of boulders.

"Listen!"

But Shann had already caught that distant rumble of sound. It was steady, beating like some giant drum. Certainly it did not herald a Throg ship in flight and it came from ahead, not from their back trail.

"Rapids ... perhaps even the falls," Thorvald interpreted that faint thunder. "Now, let's see what kind of a road we can find here."

The tongue of boulders, spiked with driftwood, was firmly based against the wall of the cut. But it sloped up to within a few feet of the top of that gap, more than one landslide having contributed to its fashioning. The landing stage paralleled the river for perhaps some fifty feet. Beyond it water splashed a straight wall. They would have to climb and follow the stream along the top of the embankment, maybe being forced well away from the source of the water.

By unspoken consent they both knelt and drank deeply from their cupped hands, splashing more of the liquid over their heads, washing the dust from their skins. Then they began to climb the rough assent up which the wolverines had already vanished. The murk above them was less solid, but again the fine grit streaked their faces, embedding itself in their hair.

Shann paused to scrape a film of mud from his lips and chin. Then he made the last pull, bracing his slight body against the push of the wind he met there. A palm struck hard between his shoulders, nearly sending him sprawling. He had only wits enough left to recognize that as an order to get on, and he staggered ahead until rock arched over him and the sand drift was shut off.

His shoulder met solid stone, and having rubbed the sand from his eyes, Shann realized he was in a pocket in the cliff walls. Well overhead he caught a glimpse of natural amber sky through a slit, but here was a twilight which thickened into complete darkness.

There was no sign of wolverines. Thorvald moved along the pocket southward, and Shann followed him. Once more they faced a dead end. For the crevice, with the sheer descent to the river on the right, the cliff wall at its back, came to an abrupt stop in a drop which caught at Shann's stomach when he ventured to look down.

If some battleship of the interstellar fleet had aimed a force beam across the mountains of Warlock, cutting down to what lay under the first envelope of planet-skin, perhaps the resulting wound might have resembled that slash. What had caused such a break between the height on which they stood and the much taller peak beyond, Shann could not guess. But it must have been a cataclysm of spectacular dimensions. There was certainly no descending to the bottom of that cut and reclimbing the rock face on the other side. The fugitives would either have to return to the river with all its ominous warnings of trouble to come, or find some other path across that gap which now provided such an effective barrier to the west.

"Down!" Just as Thorvald had pushed him out of the murk of the dust storm into the crevice, so now did that officer jerk Shann from his feet, forcing him to the floor of the half cave from which they had partially emerged.

A shadow moved across the bright band of sunlit sky.

"Back!" Thorvald caught at Shann again, his greater strength prevailing as he literally dragged the younger man into the dusk of the crevice. And he did not pause, nor allow Shann to do so, even when they were well undercover again. At last they reached the dark hole in the southern wall which they had passed earlier. And a push from Thorvald sent his companion into that.

Then a blow greater than any the Survey officer had aimed at him struck Shann. He was hurled against a rough wall with impetus enough to explode the air from his lungs, the ensuing pain so great that he feared his ribs had given under that thrust. Before his eyes fire lashed down the slit, searing him into temporary blindness. That flash was the last thing he remembered as thick darkness closed in, shutting him into the nothingness of unconsciousness.

It hurt to breathe; he was slowly aware first of that pain and then the fact that he was breathing, that he had to endure the pain for the sake of breath. His whole body was jarred into a dull torment as a weight pressed upon his twisted legs. Then strong animal breath puffed into his face. Shann lifted one hand by will power, touched thick fur, felt the rasp of a tongue laid wetly across his fingers.

Something close to terror engulfed him for a second or two when he knew that he could not see! The black about him was colored by jagged flashes of red which he somehow guessed were actually inside his eyes. He groped through that fire-pierced darkness. An animal whimper from the throat of the shaggy body pressed against him; he answered that movement.

"Taggi?"

The shove against him was almost enough to pin him once more to the wall, a painful crush on his aching ribs, as the wolverine responded to his name. That second nudge from the other side must be Togi's bid for attention.

But what had happened? Thorvald had hurled him back just after that shadow had swung over the ledge. That shadow! Shann's wits quickened as he tried to make sense of what he could remember. A Throg ship! Then that fiery lash which had cut after them could only have resulted from one of those energy bolts such as had wiped out the others of his kind at the camp. But he was still alive—!

"Thorvald?" He called through his personal darkness. When there was no answer, Shann called again, more urgently. Then he hunched forward on his hands and knees, pushing Taggi gently aside, running his hands over projecting rocks, uneven flooring.

His fingers touched what could only be cloth, before they met the warmth of flesh. And he half threw himself against the supine body of the Survey officer, groping awkwardly for heartbeat, for some sign that the other was still living.

"What——?" The one word came thickly, but Shann gave something close to a sob of relief as he caught the faint mutter. He squatted back on his heels, pressed his forearm against his aching eyes in a kind of fierce will to see.

Perhaps that pressure did relieve some of the blackout, for when he blinked again, the complete dark and the fiery trails had faded to gray, and he was sure he saw dimly a source of light to his left.

The Throg ship had fired upon them. But the aliens could not have used the full force of their weapon or neither of the Terrans would still be alive. Which meant, Shann's thoughts began to make sense—sense which brought apprehension—the Throgs probably intended to disable rather than kill. They wanted prisoners, just as Thorvald had warned.

How long did the Terrans have before the aliens would come to collect them? There was no fit landing place hereabouts for their flyer. The beetle-heads would have to set down at the edge of the desert land and climb the mountains on foot. And the Throgs were not good at that. So, the fugitives still had a measure of time.

Time to do what? The country itself held them securely captive. That drop to the southwest was one barrier. To retreat eastward would mean running straight into the hands of the hunters. To descend again to the river, their raft gone, was worse than useless. There was only this side pocket in which they sheltered. And once the Throgs arrived, they could scoop the Terrans out at their leisure, perhaps while stunned by a controlling energy beam.

"Taggi? Togi?" Shann was suddenly aware that he had not heard the wolverines for some time.

He was answered by a weirdly muffled call—from the south! Had the animals found a new exit? Was this niche more than just a niche? A cave of some length, or even a passage running back into the interior of the peaks? With that faint hope spurring him, Shann bent again over Thorvald, able now to make out the other's huddled form. Then he drew the torch from the inner loop of his coat and pressed the lowest stud.

His eyes smarted in answer to that light, watered until tears patterned the grime and dust on his cheeks. But he could make out what lay before them, a hole leading into the cliff face, the hole which might furnish the door to escape.

The Survey officer moved, levering himself up, his eyes screwed tightly shut.

"Lantee?"

"Here. And there's a tunnel—right behind you. The wolverines went that way...."

To his surprise there was a thin ghost of a smile on Thorvald's usually straight-lipped mouth. "And we'd better be away before visitors arrive?"

So he, too, must have thought his way through the sequence of past action to the same conclusion concerning the Throg movements.

"Can you see, Lantee?" The question was painfully casual, but a note in it, almost a reaching for reassurance, cut for the first time through the wall which had stood between them from their chance meeting by the wrecked ship.

"Better now. I couldn't when I first came to," Shann answered quickly.

Thorvald opened his eyes, but Shann guessed that he was as blind as he himself had been, He caught at the officer's nearer hand, drawing it to rest on his own belt.

"Grab hold!" Shann was giving the orders now. "By the look of that opening we had better try crawling. I've a torch on at low——"

"Good enough." The other's fingers fumbled on the band about Shann's slim waist until they gripped tight at his back. He started on into the opening, drawing Thorvald by that hold with him.

Luckily, they did not have to crawl far, for shortly past the entrance the fault or vein they were following became a passage high enough for even the tall Thorvald to travel without stooping. And then only a little later he released his hold on Shann, reporting he could now see well enough to manage on his own.

The torch beam caught on a wall and awoke from there a glitter which hurt their eyes—a green-gold cluster of crystals. Several feet on, there was another flash of embedded crystals. Those might promise priceless wealth, but neither Terran paused to examine them more closely or touch their surfaces. From time to time Shann whistled. And always he was answered by the wolverines, their calls coming from ahead. So the men continued to hope that they were not walking into a trap from which the Throgs could extract them.

"Snap off your torch a moment!" Thorvald ordered.

Shann obeyed. The subdued light vanished. Yet there was still light to be seen—ahead and above.

"Front door," Thorvald observed. "How do we get up?"

The torch showed them that, a narrow ladder of ledges branching off when the passage they followed took a turn to the left and east. Afterward Shann remembered that climb with wonder that they had actually made it, though their advance had been slow, passing the torch from one to another to make sure of their footing.

Shann was top man when a last spurt of effort enabled him to draw himself out into the open, his hands raw, his nails broken and torn. He sat there, stupefied with his own weariness, to stare about.

Thorvald called impatiently, and Shann reached for the torch to hold it for the officer. Then Thorvald crawled out; he, too, looked around in dull surprise.

On either side, peaks cut high into the amber of the sky. But this bowl in which the men had found refuge was rich in growing things. Though the trees were stunted, the grass grew almost as high here as it did on the meadows of the lowlands. Quartering the pocket valley, galloped the wolverines, expressing in that wild activity their delight in this freedom.

"Good campsite."

Thorvald shook his head. "We can't stay here."

And, to underline that gloomy prophesy, there issued from that hole through which they had just come, muffled and broken, but still threatening, the howl of the Throgs' hound.

The Survey officer caught the torch from Shann's hold and knelt to flash it into the interior of the passage. As the beam slowly circled that opening, he held out his other arm, measuring the size of the aperture.

"When that thing gets on a hot scent"—he snapped off the beam—"the beetle-heads won't be able to control it. There will be no reason for them to attempt to. Those hounds obey their first orders: kill—or capture. And I think this one operates on 'capture.' So they'll loose it to run ahead of their party."

"And we move to knock it out?" Shann relied now on the other's experience.

Thorvald rose. "It would need a blaster on full power to finish off a hound. No, we can't kill it. But we can make it a doorkeeper to our advantage." He trotted down into the valley, Shann beside him without understanding in the least, but aware that Thorvald did have some plan. The officer bent, searched the ground, and began to pull from under the loose surface dirt one of those nets of tough vines which they had used for cords. He thrust a double handful of this hasty harvest into Shann's hold with a single curt order: "Twist these together and make as thick a rope as you can!"

Shann twisted, discovering to his pleased surprise that under pressure the vines exuded a sticky purple sap which not only coated his hands, but also acted as an adhesive for the vines themselves so that his task was not nearly as formidable as it had first seemed. With his force ax Thorvald cut down two of the stunted trees and stripped them of branches, wedging the poles into the rocks about the entrance of the hole.

They were working against time, but on Thorvald's part with practiced efficiency. Twice more that cry of the hunter arose from the depths behind them. As the westering sun, almost down now, shone into the valley hollow Thorvald set up the frame of his trap.

"We can't knock it out, any more than we can knock out a Throg. But a beam from a stunner ought to slow it up long enough for this to work."

Taggi burst out of the grass, approaching the hole with purpose. And Togi was right at his heels. Both of them stared into that opening, drooling a little, the same eagerness in their pose as they had displayed when hunting. Shann remembered how that first howl of the Throg hound had drawn both animals to the edge of the occupied camp in spite of their marked distaste for its alien masters.

"They're after it too." He told Thorvald what he had noted on the night of their sortie.

"Maybe they can keep it occupied," the other commented. "But we don't want them to actually mix with it; that might be fatal."

A clamor broke out in the interior passage. Taggi snarled, backing away a few steps before he uttered his own war cry.

"Ready!" Thorvald jumped to the net slung from the poles; Shann raised his stunner.

Togi underlined her mate's challenge with a series of snarls rising in volume. There was a tearing, scrambling sound from within. Then Shann fired at the jack-in-the-box appearance of a monstrous head, and Thorvald released the deadfall.

The thing squalled. Ropes beat, growing taut. The wolverines backed from jaws which snapped fruitlessly. To Shann's relief the Terran animals appeared content to bait the now imprisoned—or collared—horror, without venturing to make any close attack.

But he reckoned that too soon. Perhaps the stunner had slowed up the hound's reflexes, for those jaws stilled with a last shattering snap, the toad-lizard mask—a head which was against all nature as the Terrans knew it—was quiet in the strangle leash of the rope, the rest of the body serving as a cork to fill the exit hole. Taggi had been waiting only for such a chance. He sprang, claws ready. And Togi went in after her mate to share the battle.