For long tense minutes Blake forced himself to remain rigidly motionless while Zehru labored over Mapes. Then finally the Xollarian turned his attention briefly back to Blake, and thrust two tentacles in to grip his body. No sooner had the tentacles crossed above the border of the cloth than Zehru realized that something was wrong. He tried to whip his arms back again but too late.

Blake made a lightning s.n.a.t.c.h at a tentacle with both hands, and in the same lithe movement turned from the barrier wall and flung himself headlong toward the center of the enclosure. Zehru had no time to brace himself. He was jerked bodily through the shimmering wall and on after Blake's lunging body.

One of the Xollarian's waving tentacles grasped wildly at the overhead disk in an effort to stay his flight. The only result was to bring the entire disk and its supports crashing in ruins to the ground upon the struggling figures of Blake and himself.

Blake was upon his feet again instantly. s.n.a.t.c.hing up a yard-long sc.r.a.p of metal from the wreckage of the disk, he flung himself upon Zehru.

The Xollarian seemed for the moment too dazed by his fall to fight back.

With tentacles raised to guard his head, he staggered backward in retreat, every step taking him farther away from the wall and the purple mists.

Blake was vaguely aware that Helen and Mapes, freed by the wrecking of the disk, were scrambling to their feet. Mapes was already running toward the combatants. Blake was glad at the prospect of an ally.

Zehru's dazed condition was swiftly pa.s.sing. He had now stopped his retreat and was already fumbling a tentacle toward the tube-weapon in his belt.

Blake flung himself upon Zehru in another effort to beat him down before he could draw that weapon, but his metal club glanced harmlessly off the tentacles Zehru raised to shield his head. Then beyond Zehru Blake saw something that made him stop his a.s.sault.

It was Mapes, sprinting toward the silver arch-gate at the other end of the enclosure. Blake's heart sank as he realized the gangster's treachery. If he once reached that arch he could send himself safely hurtling back to Earth, while Blake and Helen would be left to perish with Zehru in the explosion that would immediately follow. It was too late for Blake to head the gangster off. He had already covered half the distance to the arch.

Zehru noted Mapes' fleeing figure almost as quickly as did Blake.

Swiftly the Xollarian swung his tube-weapon into line with the fleeing gangster. A thin pencil of dull yellow light of a peculiar density spurted from the tube toward Mapes. There was a flash of blinding flame as the light beam met the gangster's body; then Mapes' figure seemed to literally explode, as though blasted by dynamite from within. So devastating was the force of that explosion that nothing remained of Mapes' body beyond a few scattered fragments of shoes and clothing.

Blake was still dazed at the cataclysmic suddenness of Mapes' death as Zehru swung the tube around to train it upon him. Only a last-minute desperate effort upon Blake's part saved him. His wildly thrown metal club made a lucky hit on the tube itself, knocking it, shattered and useless, out of Zehru's grasp.

Unarmed, Zehru faced Blake with his face contorting in agony. For a moment the Xollarian swayed there, apparently trying to gather his failing strength for the next move. The deadly air of the enclosure was already taking hideous toll. The scaly flesh of his head and face was dissolving like melting b.u.t.ter.

Zehru's strength was ebbing too swiftly for him to have any chance of gaining safety through either of the distant side walls. His only hope of fighting back to the purple mists was to pa.s.s Blake and go through the nearby end wall through which he had originally been drawn.

He came lunging forward in an attack whose sheer fury made Blake give ground before the menace of the lashing tentacles.

Blake took another backward step, then staggered as his foot struck a rough spot in the ground. Zehru's tentacles were upon him before he could recover himself. His club was jerked from his fingers and sent hurtling far out of reach. Half a dozen of the tentacle-arms lashed around his throat in a strangling grip.

He clawed wildly at the choking coils, but they failed to loosen even a fraction of an inch. Desperately Blake sent his fists smashing into the gray face. The scale armor of Zehru's skull, fast weakening in the liquefying influence of the oxygen, gave way beneath that battering attack. He staggered, and his coiling tentacles relaxed slightly.

Blake tore himself free. A final smashing blow, with every ounce of his one hundred and ninety pounds behind it, sent Zehru crashing to the ground. The Xollarian tried to rise, then feebly slumped back, his strength spent. Blake leaped forward to finish his opponent, but stopped as he saw that his efforts were not needed.

The deadly air of the enclosure was now overwhelming Zehru with swift and hideous death. He was literally rotting before Blake's horrified eyes, the gray-scaled skin sloughing off in streaming rivulets of pallid ooze, and the entire body contorting in what was obviously a death agony.

Sickened, Blake stepped back a pace or two. Zehru's tentacles feebly beat the ground around him, then suddenly one of the writhing arms blundered upon a thin cable running along the ground. Before Blake could spring forward to stop him, Zehru with a last surge of power ripped the fragile metal strand completely in two.

It was the Xollarian's dying effort. He slumped in a motionless, nearly liquescent heap. But that last blind blow at the Earthlings threatened to be a deadly one. The severed cable led to one of the black posts surrounding the enclosure. With the cable's parting an entire section of one of the gold-flecked barrier walls vanished. Xollar's deadly purple mists were already surging in.

Speed was the Earthlings' only chance now. Helen was as quick to realize the danger as was Blake. Side by side they started their mad race toward where the silver arch-gate loomed nearly a hundred yards away.

They had covered barely half the distance when the air around them began to show a definite tinge of purple. With the appearance of the purple hue there came a strange and swiftly increasing agony, a torturing vibration that seemed to be tearing every atom in their bodies asunder.

They were within ten yards of the arch when Helen fell. Blake grabbed her up in his arms and stumbled on. There was no longer enough oxygen in the air to even breathe. Blake's lungs were on fire. Every cell in his body seemed vibrating in unbearable torment.

It was all that he could do to struggle up on the low platform. He staggered across the s.p.a.ce and under the arch. It took the last shred of strength in his tortured body for him to lift his hand and pull the black lever down into place.

Its action was instantaneous. The agony of the purple mists was blotted out in a surging wave of mighty force that swept Blake and Helen up and away through a s.p.a.celess universe where black chaos reigned awesomely supreme. There was a long terrible moment of hurtling through distances inconceivably vast. Blake's brain reeled in nausea.

Then suddenly all motion ceased and everything was normal again. There was firm gra.s.sy ground under his feet and a cool breeze was blowing in his face.

He opened his eyes and saw the gray half-light of early dawn. After the first swift look around him he sighed in mighty relief. To his left was the familiar skyline of Fifth Avenue. To his right was Central Park West. They were somewhere in Central Park, safe again in their own world.

And somewhere in that other world beneath the twin purple suns, the time mechanism of the silver gate should even now be releasing the explosive that would forever blot out all trace of the evil handiwork of Zehru, cosmic fisher of Xollar.