They fastened the gla.s.ses over their eyes, keeping the helmet face-plates partly open. The rayguns they eased in their belt holsters, and slid back the hinged palms of their mittens, to give exit if need be to their gun-hands. They were ready.

Switching on the helmet gravity-plates to swift repulsion, the three soared out of the trees, soared up on a straight, inclined line for the dome on the asteroid, a steady, rapid climb that soon raised them one mile, a second and a third, where they leveled off and sped straight ahead. Now they could look right into the dome.

Rapidly the port-lock that was their objective grew in size. Behind it were the buildings: the large, four-winged central structure and the supplementary workshops and hangars, coolie-quarters and outhouses, all dim and shimmering through the infra-red--the mysterious, lonely citadel of Dr. Ku Sui. There it all was, inside the dome, with the rest of the asteroid looming ma.s.sive behind.

A quarter-mile away, and swiftly half that, and half again the three grouped figures arrowed ahead without hesitation. And the Hawk said curtly:

"I see no men--do either of you? It looks deserted."

"There!" cried Ban, after a second. "There! Beside the port-lock. Just now!"

Beside the smaller port-lock's inner door a figure had appeared, clad in the neat yellow smock of a servitor of Ku Sui. It was a smooth, impa.s.sive Oriental face that turned to stare out at the approaching men; and even Ban knew that this sentinel stationed at the lock was one of the coolies whose brains Dr. Ku had altered, turning him into a mechanicalized man who obeyed no orders but his. He watched closely the three who swept on towards him, his hand at a raygun in his belt.

The same questions were in the minds of all three of the raiders.

Would he recognize something as being different, or suspicious? Would he summon others of his kind from the small guard-box he had come out of?

But the coolie evinced no alarm. It would have been difficult for anyone to have discerned distinguishing features inside the c.u.mbersome helmets, behind the instruments clamped to the faces of the men who wore the suits. He called no others, but merely watched.

Soon the opaque metal plates of the small lock's outer door had neared to within a few feet of Hawk Ca.r.s.e, and he stopped short, Ban and Friday following suit. They hovered there outside the door, gently swaying like flies against the great gleaming sweep of the dome, the craggy rock face dropping sickeningly down for miles beneath them.

And, like flies, they were powerless to open the door to gain entrance. Only the coolie inside could do that; and he, through the dome to one side, was peering at them.

Apparently he was satisfied with his scrutiny. After a moment, bolts shifted and the door stirred and swung out, revealing the all-metal atmosphere chamber and the inner door at the far side. Immediately Ca.r.s.e floated into the chamber, and the two others pressed in behind.

They saw the outer door swing shut, and heard its locks thud over.

They were sealed from sight inside the port-lock's atmosphere chamber.

"Looks to me," whispered Ban Wilson, "like a very sweet trap. If that fellow inside wants to--"

The Hawk's cool voice cut him off.

"We can take off the gla.s.ses now," he said casually. "Keep alert."

And for a full minute they waited.

At length a circle of light showed around the rim of the inner door, and it grew quickly into the full flood of Jupiter-light as the door opened.

Ca.r.s.e floated through, no longer attempting to avert his face.

The coolie, standing just outside the chamber, saw the adventurer's features and remembered--and drew the raygun in his belt.

Ca.r.s.e did not shoot. He never killed unless he could not avoid it; this was as much a part of his creed as his remorseless leveling of a blood-debt. He struck with the suit. Under a quick turn of the control, the great heavy bulk of fabric-joined metal lunged forward.

The move was quick, but not quite quick enough, for just before the coolie was bowled headlong to the ground, he got out a high-pitched warning yell; and then, as he lay sprawled out, apparently unconscious, a thin hot orange streak sizzled by Hawk Ca.r.s.e's helmet from the left.

This time Ca.r.s.e shot. His gun leaped from belt to hand, and had twice spoken from the hip before one could quite grasp what had happened.

Seemingly without bothering to take aim, his deadly left hand had stricken into lifeless heaps two coolies who had come running and shooting from the nearby guard-box.

As Ca.r.s.e stood looking down at their bodies he was startled by another sizzling spit. He wheeled to see Friday holding the raygun that had spoken.

The Negro said apologetically:

"Sorry, suh--I had to. The other coolie, the one you knocked down, came to and was aimin' at you. Guess they're all three dead now, sure enough."

His master nodded, and said in a low, thoughtful voice: "In spite of what some men have said, I never like to kill; but for these robots, more machines than men, with nothing human to live for, it's release rather than death.

"Well," he began again, more briskly, "we're inside, and whoever else is here apparently doesn't know it yet. I expected more of a commotion. I wonder how many coolies Ku Sui had, altogether? Fourteen or fifteen were killed when we broke through the dome, before, and now these three. There surely can't be many left. Of course, there are the four white men, his surgical a.s.sistants."

Ban Wilson spoke after what was for him a long silence. He had watched the Hawk's gunplay with an awe-stricken face; its speed never failed to amaze him. He observed:

"These buildings certainly look lifeless. Well, what now, Ca.r.s.e?"

"A search." He planned it out in his head, then gave quick orders.

"Ban," he directed, "you go through all the out-buildings, your gun ready. The five main ones are a workshop, a power-house, storehouse, a ship hangar and a barracks for coolies. Whoever you find, take prisoner. Keep in touch with me by radio."

"Friday," he continued, "I'm leaving you here. First get these bodies in that guard-house they came out of. Then keep sharp watch. I don't think Ku Sui will return within fifteen minutes, but we must take no chance. At the first sign of him, warn me."

"Yes, suh. But what are you goin' to do?"

"Take over the central building," said the Hawk. "And then, when the whole place has been reconnoitered, fulfil my promise to the brains."

"And what about Ku Sui?"

"Later," he said. "It should not be hard to take him prisoner.... Now, enough!"

The three parted.

CHAPTER IV

_The Voice of the Brains_

The central structure of the group of buildings was shaped like a great plus-mark, each of its four wings of identical square construction, with long smooth metal sides and top, and with a door at the end giving entrance to a corridor that ran straight through to the chief central laboratory of Dr. Ku Sui.

Ca.r.s.e skimmed swiftly, two feet off the glittering metallic soil, towards the end of the nearest wing, where he gently landed. He tried the door giving entrance. It was open. He cautiously floated through into complete darkness.

The Hawk was prepared for that. He drew a hand-flash from the belt of his suit, and, standing motionless, his raygun ready in his left hand, he probed the darkness with a long white beam. s.p.a.ced evenly along the sides of the corridor were many identical doors, and at the end a larger, heavier door which gave entrance to the central laboratory. He found no life or anything that moved at all, so, methodically, he set about inspecting the side rooms.

The doors were all unlocked, and he moved down the line without alarm, like a mechanical giant preceded by a sweeping, nervous flow of light.

Such he might from the outside have appeared to be, but the man within himself was more like a cat scenting for danger, all muscles and senses delicately tuned to alertness. Door by door, a cautious and thorough inspection; but he found nothing of danger. All the rooms of that wing were used merely for stores and equipment, and they were quite silent and deserted. When he came at last to its end, Ca.r.s.e knew that the wing was safe.

He paused a minute before the laboratory door. He had expected to find it locked, and that he would have to seek other means of entrance; but it was not. By pushing softly against it, it easily gave inward on silent well-oiled hinges. He entered.