"Jupiter! What\'s that?" Mado unslung his torpedo-projector.

As if in answer to his startled question, a weird object drifted over the treetops and poised directly above them, about fifty feet up. An egg-shaped thing, six or seven feet in length, and seemingly made of white metal. It swayed there gently, without visible means of support, and they could make out a transparent disk on its side, back of which there was a human head with eyes that regarded them curiously.

Mado raised his torpedo tube and took aim.

"Hold it!" Carr warned him. "This fellow\'s no savage. Probably he\'s one of those who tried to break our fall. Friendly, perhaps."

Two more of the ovoids drifted in from the woods and joined the first one, all three settling a few feet lower and their occupants staring intently at the intruders.

"I\'ll get the psycho-ray apparatus," Detis said excitedly. "We may be able to get thought contact with them." He dived through the Nomad\'s entrance-manhole as he spoke.

"Nothing so frightening about these creatures," Ora murmured, her eyes reproaching Carr. "Why, they seem anxious to know that we are not enemies."

And, indeed, this seemed to be the case, for the strange ovoids wafted still lower, dropping until a faint humming of the internal gravity mechanism came to their ears. These were a highly developed people of scientific attainment; civilized beings. But Mado kept firm hold of his torpedo tube, and Carr fingered the ray pistol at his belt.

The booming note from the hills came then, frightfully near this time, and the three ovoids moved with sudden roaring of their motors, literally hurling themselves skyward. But the menace they sought to escape was real, and not to be outdone in speed. A vast black something whirred out from beyond the treetops and flung itself upon them.

"A pterodactyl!" Mado gasped. "One of the prehistoric monsters of Terra!"

"Carr, there are men riding it!" Ora exclaimed. "Red men!"

It was true; the pteranodon, a horrid bat-like thing with a wing-spread of fully twenty feet, carried three of the bronzed savages clinging to a sort of harness that encircled its body just back of the crested head. The huge flying reptile whistled raucously as it flew and one of the savages was whirling a sling which held a stone as large as his own head. They watched in amazement as the swift aerial steed flapped its way after the rising ovoids. And then the savage let loose an end of his thong and released its missile, which crashed full against the transparent disk of an ovoid and tore its way through.

The damaged ovoid careened violently and then fell end over end, crashing in the forest. With a bellow of fury, Mado fired with the kalbite tube at his hip. There was the twang of the propelling ray, and the slender arrow-like torpedo sped forth on its message of death, singing spitefully as it cleaved the air of Titan.

It was a fair hit, catching the pteranodon just ahead of its trailing legs and exploding with the characteristic screaming roar of the deadly kalbite. The monstrous reptile and its crew of barbarians vanished in a blaze that lighted the clouds above them and brought a babble of excited shoutings from the depths of the forest on all sides. They were surrounded by the uncivilized ones of Titan! And those of the ovoids had run off at the first sign of danger.

The din from the forest was augmented by the whistlings of a second pteranodon which darted after the remaining ovoids, following swiftly as these retreated with ludicrous, wabbling haste.

Ora screamed and struck out at something with her fist. A naked arm had reached out from the underbrush and grasped her wrist. Carr wheeled and his ray pistol spat crackling flame. The savage, an undersized red man with an enormous head, rose unsteadily from his hiding place, a look of terrible hate in his contorted features. Then, like a punctured balloon, his body collapsed into the nothingness of complete disintegration.

"Back, back to the Nomad!" Carr roared, dragging Ora with him and leveling his pistol at a group of the bronze brutes who rushed into the space where the vessel lay amongst the trees.

Mado was busy with his torpedo tube and a vast explosion shook the ground beneath them as a trio of the savages were blasted out of existence. A great tree toppled and crashed across the nose of the Nomad, its roots ripped from the soil by the concussion.

Ora had whipped out her own pistol and was firing as they fell back. Game kid, she was! Carr gloated as he saw she was making each shot tell. But this couldn\'t last; there were hundreds of them now, long-armed and big-headed red devils swarming in from every direction. Carr dodged none too quickly to save his skull from a swift-flung stone, which clanged against the Nomad\'s hull. There was a perfect hail of the missiles now: one struck his left arm a numbing blow, and he heard a sickening thud and Ora\'s moan as she was hit. And there were winged darts, from blow-guns.

A dusky moon-face leered into his own, horribly close, and he yelled his rage as he drove it back with a swift uppercut. But the horde of savages came on in ever increasing numbers and with renewed vigor.

"Quick—inside!" Carr hissed in Ora\'s ear as his fingers found the rim of the manhole. He\'d have her safely within in a moment.

Detis clambered out with the thought machine in his arms, and a singing dart from one of the blow-guns pierced him through and through. A look of astonishment spread over his kindly features, and he fell forward, dying.

And then Carr looked up into a grinning face behind a huge club that was swinging downward. He threw up his arm to break the force of the blow, but the club fell too swiftly; the enormous weight of it crashed down on his skull, and he knew no more.

When he awakened it was to stare for a dazed moment into a pair of blue eyes that looked down upon him in a place of dim light and stuffy atmosphere. The eyes were only vaguely familiar in his befuddled memory. Beautiful eyes, though, and incredibly dear....

"Ora!" he exclaimed, in wondering remembrance, trying to sit up as he grasped her hand.

"Hush!" she warned him, placing a finger-tip to his lips. "Be quiet now and perhaps they\'ll leave us alone for a while."

"They! Did they capture us?" he whispered. "Are you hurt?"

"We\'re prisoners, all right, excepting poor father. But they didn\'t harm me much, outside of the rough handling."

"The devils. What of Detis?" He was growing stronger by the minute and now saw that they were in an open-mouthed cave and that Mado was sitting hunched dejectedly in a corner, his massive shoulders drooping and his proud head bowed on his chest.

"Father—they killed him," Ora sighed almost inaudibly. "Have you forgotten? We saw the dart strike him and I—I saw it sticking from his chest. Oh, Carr!" A dry sob caught in her throat.

"Yes—yes. Lord!" Carr groaned, sick at heart with the sudden recollection and full of compassion for the stricken girl.

He patted her hand with clumsy tenderness as she turned her head and gazed out through the cave mouth in silence that was fraught with intense pain. She would take it like that: with little to say but with much inward suffering.

And then he noticed a fourth occupant of the cavern, a young lad of Titan. Like one of the savages in his small stature and in the large size of his head, he was much lighter in color and his body was encased in a snug one-piece garment of shimmering material of silky texture. And there was a different light in his eyes, the light of intelligence and culture.

"Who is that?" Carr whispered.

Ora stared when she saw that the stranger was on his feet. "Oh," she exclaimed, "I\'m glad he has recovered. He\'s one of the civilized ones; they captured him with his ovoid when the second pteranodon went out after them."

Mado was standing now, endeavoring to communicate with the lad by means of signs and the drawing of crude pictures in the red sand of the cavern floor. The graceful little fellow watched him with understanding and with a smile of amused tolerance. Then he halted the big Martian with an imperious motion, addressing him in velvety voice.

"Nazu," he said simply, placing a forefinger on his breast and bowing before the astonished Mado.

"Imps of the canals!" the Martian exclaimed, grinning delightedly as he cast a swift look at Carr and Ora. "He\'s telling me his name." "Mine\'s Mado," he said, turning his eyes to the keen gray ones that smiled up at him. "Mado," he repeated, placing a huge fist against his own chest and bending his body in awkward imitation of the lad\'s courtly gesture.

They made no attempt to converse in tongues that would convey no meaning, but there was no mistaking the quick friendship that sprang up between the incongruous pair. Mado was the boy\'s slave from that moment, and Nazu looked up to the Martian with all of youth\'s admiration for his vast bulk and rippling muscles.

Suddenly they were without light and Carr saw that a curtain of woven rushes had been dropped over the mouth of the cave. There were soft padding footsteps on every side and he drew back against the rock wall with Ora clasped in his arms. A sinewy hand grasped his wrist and twisted his right arm free. He lashed out in the darkness and was rewarded by a grunt of pain as his fist contacted with an unseen face. Nazu\'s voice rose in anguish, and Mado\'s wrathful bellow was followed by a frightful commotion as he tore into his assailants.

They were everywhere in the blackness, these slippery little savages of Titan, their half naked bodies crowding him and stifling him with their sweaty nearness. Again and again Carr struck out, but it was like fighting a horde of squirming and clawing feline creatures that swarmed over him and bore him down by sheer weight of numbers. They dragged Ora from his arms and quickly overpowered him. Thongs of rawhide twisted deeply into the flesh of his wrists and he was hauled forth into the daylight.

Securely tied, hand and foot, Carr was propped............