held the Earthlings as effectively and hopelessly prisoners in their enclosure as gold-fish in a bowl of water.

Blake turned back to the thicket to see how Helen and Mapes had fared in that terrific battle with the headless things. He was relieved to see that the girl had apparently escaped without even a scratch. She was kneeling beside Mapes' prone figure, doing what she could to revive him. The gangster was badly battered, but he seemed to have no serious injuries. He was already beginning to stir weakly and show signs of returning life.

Blake started to step over to the two. Then he stopped abruptly as he heard a sharp metallic clang from the cone-building out in the purple mists beyond the end wall. He looked quickly up and saw that an oval window had opened in the structure near its tip. Framed in the opening was what seemed to be a large concave mirror. At one side of the mirror was a living being of some kind, but the intervening mists prevented Blake from making out any details beyond a hazy glimpse of a cluster of what seemed to be long slender snake-like black tentacles.

The next moment there spurted from the mirror a broad and swiftly spreading beam of red light so brilliant that it glowed clearly even in the bright purple rays of the twin suns. Before Blake could shout a warning to Helen the racing flood of ruddy radiance was upon them. The scene reeled in a blurred kaleidoscope of flaming colors before Blake's eyes for a brief second, then complete oblivion swept over him.

After an interval that seemed hours, consciousness returned to him as suddenly as it had left him. His first bewildered look around him disclosed the fact that startling changes had occurred in his surroundings during the period while he was under the anesthesia of the red ray.

His first effort at movement brought realization that he was in the grip of a strange paralysis. His head and neck seemed quite normal in every way, but from the throat downward his body was completely dead as far as any power of voluntary movement was concerned.

He twisted his head stiffly to one side, and saw that Helen was standing there beside him. Just beyond her was the motionless figure of Gil Mapes. Both the gangster and the girl were in the grip of the same strange paralysis. Like Blake, they were standing there rigidly motionless, facing the gold-flecked barrier wall just in front of them.

A moment's painful scrutiny of their position showed Blake that the posts forming the wall of the enclosure at the end toward the cone had been brought in nearly a hundred yards toward them while they slept. The shimmering barrier sheet was now scarcely a yard from their faces, yet they still stood near the thicket where they had battled the headless horrors. Blake saw his coat half-buried in the blue-gray dust near his feet where Helen had discarded the garment to minister to Mapes.

Their unseen captor had obviously made definite preparations for whatever his next purpose with them was to be, for a long wheeled platform had been brought to a position opposite them just outside the shimmering gold-flecked sheet. Blake noted the shattered remains of Mapes' pistol on the ground at one side of the platform. It had apparently been fished from the enclosure and rendered harmless after their captor had seen the weapon's efficient use against the headless ape-things.

Clustered upon the wheeled platform was an assemblage of intricately winding coils, glowing tubes, and other apparatus that conveyed no more meaning to Blake's bewildered gaze than a sight of the interior of a metropolitan power-house would to a Congo savage.

There was only one piece of the apparatus regarding whose probable function Blake could even guess. This was a pair of long slender arms that projected through the shimmering walls into the enclosure, supporting at their end a large thin metal plate located just over the heads of the three Earthlings. Blake was willing to wager that it was this overhead plate that was responsible for the odd paralysis that held them helpless.

Then a figure came slowly into view from where it had been concealed by the apparatus, and Blake forgot all thought of the strange mechanisms as he watched the monstrous thing clamber stiffly from the platform and halt squarely in front of the captives to stare at them through the transparency of the intervening force sheet.

The thing was a curious blending of human and bestial features. It stood barely five feet in height, yet its great scale-armored skull was at least three times as large as that of a grown man. There was colossal mental power and nameless evil glowing in the dark depths of the two abnormally large eyes that stared fixedly out from under the heavy forehead. The thing had no nose. The mouth opening, surrounded by a rosette of flabby gray skin, was a mere slit. The entire skull and face were covered with small, closely overlapping scales of lusterless gray.

The head merged directly into a short black torso nearly as wide as the skull itself. From this trunk there writhed a score of long black snake-like tentacles, each terminating in a flexible three-fingered "hand." The trunk was supported by two short thick legs, armored with gray scales, and ending in broad three-toed feet.

"Greetings, Earthlings!" The voice that emanated from the grotesque mouth was surprisingly resonant in tone. "Allow me to present myself. I am Zehru, imperial scientist of Xollar."

The monstrosity seemed amused at the expressions of blank surprise upon the faces of his captives. "I learned your crude language from your brain cells while you slept under the red ray," he explained. "Also I learned many other things regarding your planet, Earth. I am glad to find your world so well adapted to my purpose. Within a few years after my arrival there I shall be its unquestioned ruler."

Blake started to voice the many questions that were surging through his mind, but an imperious gesture of an outflung tentacle stopped him.

"Silence, Earthling!" There was tolerant contempt in Zehru's ringing voice. "I will explain some of the things that puzzle you. There is no reason why I should trouble myself to do so, yet it may while away the tedium of the short wait yet remaining before my apparatus becomes charged to the required point. Listen carefully, Earthling, for at best you will find many of my thoughts beyond the feeble limits of the word forms with which you have provided me.

"The world of Xollar, where you now are, is a planet in the island universe known to your astronomers as the Great Nebula of Andromeda. Until a short time ago I was one of its ruling scientists. Then I sinned, and so grave was my sin according to the laws of this planet that the Council of Three decreed my death. That death sentence upon Xollar is irrevocable, and no man has yet escaped it no matter where upon the planet he may be when the appointed time for his execution comes. I was given the usual period of grace in which to put my affairs in order. Instead, I have labored unceasingly here in my laboratory, and my labors have borne fruit. I am the first man in Xollarian history to find a means of escaping the dread death penalty.

"Briefly, I discovered a way by which I can flee to your far-distant universe, where not even the powers of the Council of Three can follow me. That way lies through the door of inter-dimensional Space. In Space as you know it, the almost unthinkable distance of a million light years separates Xollar from the dwarf star you call your Sun. Yet, traveling between Space, the two planets nearly touch each other. The same situation of being near neighbors in inter-dimensional Space holds true with Xollar and at least seven other planets located in widely separated parts of your universe.

"Let me try to illustrate what