"You're taking it for granted that he's still alive," Illya said. "I'm afraid I'm not that optimistic."

"I'm only optimistic about one thing," Solo said. "A desert waste where there's little or no rainfall and travelers are rarely encountered can stay unchanged for weeks. If we search carefully we may find some clue as to precisely what happened—evidences of a struggle perhaps, or footprints leading in just one direction."

"I guess I can buy that," Illya said. "Onward then, with stout hearts and banners flying."

Solo looked back and saw that Sun Lin's two desert-tracking companions had halted their camels some sixty feet from where he had dismounted with Kuryakin and the enigmatic oriental. He gestured for the journey to be resumed, remounting his own camel as he did so.

A moment later all five camels were jogging onward again over an almost level expanse of sand, with Solo and Kuryakin rewarding their untiring mounts with occasional hump-pattings which the camels seemed to appreciate, for it caused them to move at a slightly faster pace. They were quite different from fast-stepping horses, however, and though they could outdistance the wind in speed under the goadings of desert raiders they seemed to prefer to move in much more leisurely fashion.

The twilight which preceded the coming of darkness was of short duration, and before an hour had passed the sky was sprinkled with stars and a crescent moon had made its appearance amidst fleecy clouds close to the desert's rim.

They continued on for another hour, with Solo and Kuryakin slightly in the lead. Then, abruptly, Sun Lin halted his camel and pointed out across the sand to where a gigantic ridge of stone bisected the desert.

"It is near this spot that the American you seek was last seen," Sun Lin said.

"FOR MILES the landscape has been featureless," Napoleon Solo said. "And now we run into some thing like this, a rock formation that looks as if it had dropped down out of the sky with a Made on Mars label on it."

"It looks more like one of those rugged lunar landscapes we've been getting moon-probe photographs of," Kuryakin said. "It's honeycombed with caverns, but they can't be very large. Just pitted indentations, I'd say. The entire structure can't be more than a hundred feet in length."

"Do you suppose it actually did fall from the sky?" Solo said. "A meteor that large may have landed on Earth more than once. There was that Siberian one that splintered into fragments and shook up about a third of Russia."

Illya shook his head. "I don't think it's anything but a natural Gobi rock formation," he said. "It's only slightly weather-eroded, you'll notice, with no blasted out surfaces."

"Anything is possible in the Gobi. Is that what you're trying to say? I'm beginning to feel you could be right. In a legend-haunted desert—"

Illya Kuryakin smiled wryly. "Actually, there's nothing geologically unusual about a big rock castle in a desert that's as vast as the Gobi. It could be just a mountain that got tired of fighting its way up through ten or twelve million tons of sand when the earth was young."

"There's a lesson in that for us," Solo said. "We can't afford to get tired so early in the game. Tomorrow or the next day a sandstorm could bury us, along with every trace of what we came here to find."

"Right," Illya agreed. "Maybe we should start searching right now."

"It will be less of a risk in the morning," Solo said. "Everything will stand out clearly and sharply. And we're practically out on our feet. There's only one right way to start a search when the time factor isn't of primary importance. The slow, careful way, skipping nothing, going over every inch of the ground."

"I guess you're right," Illya said. "I'll help Sun Lin and his boys get the tents unrolled. Otherwise it will take them half the night."

Pitching camp for the night in a desert waste was the opposite of a simple task. This Solo had discovered for himself several times in the past. His admiration for Sun Lin and that tireless oriental's two companions was boundless as he watched the swift and efficient way the tent poles were taken down from the camels, the canvas stretched out on the sand, the sleeping mats inspected for the possible presence of vermin and shaken out in the windless air.

His admiration increased when Sun Lin took barely five minutes to get the camels bedded down for the night in a comfortable hollow in the sand. Then the tents went up and that, too, was a gratifying thing to watch when aching bones and throbbing temples made six or seven hours of sleep a luxury to be prized.

The entire task took about twenty minutes in all and it was surprising how much like a miniature tent city the entire arrangement looked. Just two tents, four drowsy camels and several wooden stakes driven in a circle into the sand gave the camp site a community look which was pleasant to contemplate with the moonlight shining down.

Neither Solo nor Kuryakin spent more than two or three minutes wrapped in contemplation, however, for they were out on their feet. Just crawling on their hands and knees into the cool interior of a tent and flopping down on sleeping mats seemed the wisest thing to do.

Five minutes after they had drawn the tent flap shut behind them they were sleeping soundly.

EIGHT

VIOLENCE IN THE SMALL HOURS

IT WAS not a gunshot which awakened them. It was a scream, agonized, prolonged, a scream that went on and on.

They awoke in total darkness, with no knowledge of the time, hearing only the scream shattering the silence of the night.

Solo was the first to leap to his feet, tighten the belt of his tropical shorts and rush out into the night, stopping only for an instant to give Kuryakin a resounding slap on the shoulder and shout a warning, on the off chance that he had not come fully awake.

But Illya was awake enough, and it took him only an instant to snatch a round of ammunition down from the tent pole and strap a holstered gun to his waist, a precaution which Solo had been in too much of a hurry to take.

The instant he emerged from the tent he saw that Napoleon Solo had already crossed the wide stretch of sand which separated the tent from the long rock structure which they had encircled in puzzlement before turning in for the night and was struggling with someone about his own height who had thrown one arm about his neck and was making a frantic effort to drag him to the sand.

Knowing that Solo was unarmed and that the struggling figure might well be clasping a knife made Illya break into a run without stopping to upholster his gun.

That his fear was justified he saw before he had crossed half of the intervening distance, for the sudden glint of moonlight on steel was unmistakable. The knife flashed twice and each flash was accompanied by a downward thrust of the attacking figure's left arm. Solo groaned loudly and fell to one knee. But he was almost instantly on his feet again, fighting desperately to keep the knife at arm's length.

Illya managed to get his gun out of its holster as he ran. But the two men were so entangled now that to risk a shot at Solo's assailant would have been the height of folly. But still he kept the weapon, a .38 calibre special, leveled and ready, his forefinger on the safety catch.

He crashed into the man just as his arm was going up for the third time, and Solo had started to sag, his right sleeve drenched with blood.

Reversing the pistol, Illya Kuryakin brought the butt-end down with violence on the maniacal knife-wielder's skull. But the knife continued to rise, the hand that held it thrusting upward with a violent jerk that carried the weapon high into the air. Then the man's arm fell back to his side and the knife dropped to the sand. He crashed down on top of it, rolled over and lay still.