He leaped to his feet. Staring around, he wondered if he could retrace his steps back to the space-ship. And in that precise moment he felt his mind seized again with a sort of frantic suddenness. There was no mistaking that very clear warning of, "_Danger! Danger!_" But he could not have acted in time. Even as he spun around he was unaware of the shadow that lengthened behind him, until it loomed very near and a part of it lashed out. Not until the last split second, did Hugh glimpse wild and red-streaked eyes in vivid contrast to the grim and purposeful face behind a helmet plate. Then the part of the shadow that was Jim Brannigan's arm, holding something massive like a rock, completed the swift arc and struck. A sun exploded within Hugh's head. Livid flames engulfed him, consumed him, he tried to cry out but couldn't; then the sun fragments cruelly withdrew, leaving him helpless in a cold blackness through which he fell like a plummet to ultimate extinction. * * * * * Jim Brannigan stood there tensely for a moment, looking at the man he had struck down. But only for a moment. His lips quirked into a tight smile, and his exulting keen eyes took in the cave's glittering expanse. "A fortune in oxide crystals," he murmured, "an inexhaustible mine! And he thought he could cheat me out of it, keep it from me! Good thing I followed him. Serves him right if I've killed him." He didn't seem too worried about it, and he didn't look at Hugh's body again as he started gathering in the rare crystals. "Europa's uncharted, I can claim-deed this whole region! And probably there's another fortune in furs," he added as he suddenly remembered the creature he had captured. Already, in his greedy mind's eye, he saw himself a tycoon, the oxide king, with a corner on furs finer than anything ever seen on Earth, Venus or Mars. This he saw. But what he didn't see were the myriad pairs of burning beryl eyes peering at him from concealed openings in the opaline walls. He was not aware of the increasing energy potential being generated by a growing legion of furred bodies in surrounding caverns, as more and more Panadurs pressed forward to peer out at him. Around Jim Brannigan now the frigid atmosphere began to rise. At first it was pleasantly cool, then warm, and warmer, until it became suffocating. Still the silvery-furred Panadurs, in utter silence, generated heat as their mental forces grew and deliberately united into a single, increasing potential. Their fur stood erect, an angry violet-silver now, crackling a little with the intensity of the effort. As a single unit, they waited, each furry Panadur now touching the other in a living, livid chain of cumulative power. Jim Brannigan ceased his gloating and awoke at last to an indefinable danger. Swiftly he arose and whirled toward the entrance, peering back over his shoulder at the danger he could feel, that he knew was there, but could not see.