He opened his eyes, and was almost blinded when he found himself staring at a whitish heaven where blown columns of steam went by like spectral genii. Just below the rim of his vision, there was something vast and incandescent, toward which, instinctively, he feared to turn. Suddenly he knew what it was, and began to realize his situation. Memory came to him in a tumbling torment of images; and with it, a growing wonder and alarm.

He recalled the ramble he had taken, alone, amid the weird and scrubby jungles of the twilight zone of Mercury—that narrow belt, warm and vaporous, lying beneath the broiling deserts on which an enormous sun glares perpetually, and the heaped and mountainous glaciers of the planet’s nightward side.

He had not gone far from the rocket-ship—a mile at most, toward the sulphurous, fuming afterglow of the sun, now wholly hidden by the planet’s libration. Johnson, the head of that first scientific expedition to Mercury, had warned him against these solitary excursions; but Howard, a professional botanist, had been eager to hasten his investigations of the unknown world, in which they had now sojourned for a week of terrestrial time.

Contrary to expectation, they had found a low, thin, breathable atmosphere, fed by the melting of ice in the variable twilight belt—an air that was drawn continually in high winds toward the sun; and the wearing of special equipment was unnecessary. Howard had not anticipated any danger; for the shy, animal-like natives had shown no hostility and had fled from the earth-men whenever approached. The other life-forms, as far as had been determined, were of low, insensitive types, often semi-vegetative, and easily avoided when poisonous or carnivorous.

Even the huge, ugly, salamander-like reptiles who seemed to roam at will from the twilight zone to the scalding deserts beneath an eternal day, were seemingly quite inoffensive.

Howard had been examining a queer, unfamiliar growth resembling a large truffle, which he had found in an open space, among the pale, poddy, wind-bowed shrubs. The growth, when he touched it, had displayed signs of sluggish animation and had started to conceal itself, burrowing into the boggy soil. He was prodding the thing with the sponge-like branch of a dead shrub, and was wondering how to classify it, when, looking up, he had found himself surrounded by the Mercutian savages. They had stolen upon him noiselessly from the semi-fungoid thickets; but he was not alarmed at first, thinking merely that they had begun to overcome their shyness and show their barbaric curiosity.

They were gnarled and dwarfish creatures, who walked partially erect at most times; but ran upon all fours when frightened. The earth-men had named them the Dlukus, because of the clucking sounds resembling this word which they often made. Their skins were heavily scaled, like those of reptiles; and their small, protruding eyes appeared to be covered at all times with a sort of thin film. Anything ghastlier or more repulsive than these beings could hardly have been found on the inner planets. But when they closed in upon Howard, walking with a forward crouch and clucking incessantly, he had taken their approach for a sort of overture and had neglected to draw his tonanite pistol. He saw that they were carrying rough pieces of some blackish mineral, and had surmised, from the way in which their webbed hands were held toward him, that they were bringing him a gift or peace-offering.

Their savage faces were inscrutable; and they had drawn very close before he was disillusioned as to their intent. Then, without warning, in a cool, orderly manner, they had begun to assail him with the fragments of the mineral they carried. He had fought them; but his resistance had been cut short by a violent blow from behind, which had sent him reeling into oblivion.

All this he remembered clearly enough; but there must have been an indefinite blank, following his lapse into insensibility. What, he wondered, had happened during this interim, and where was he going? Was he a captive among the Dlukus? The glaring light and scorching heat could mean only one thing—that he had been carried into the sunward lands of Mercury. That incandescent thing toward which he dared not look was the sun itself, looming in a vast arc above the horizon.

He tried to sit up, but succeeded merely in raising his head a little. He saw that there were leathery thongs about his chest, arms and legs, binding him tightly to some mobile surface that seemed to heave and pant beneath him. Slewing his head to one side, he found that this surface was horny, rounded and reticulated. It was like something he had seen.

Then, with a start of horror, he recognized it. He was bound, Mazeppa-like, to the back of one of those salamandrine monsters to which the earth-scientists had given the name of “heat-lizards.” These creatures were large crocodiles, but possessed longer legs than any terrestrial saurian. Their thick hides were apparently, to an amazing extent, non-conductors of heat, and served to insulate them against temperatures that would have parboiled any other known form of life.

The exact range of their habitat had not yet been learned; but they had been seen from the rocket-ship, during a brief sunward dash, in deserts where water was perpetually at the boiling point; where rills and rivers, flowing from the twilight zone, wasted themselves in heavy vapors from terrible cauldrons of naked rock.

Howard’s consternation, as he realized his plight and his probable fate, was mingled with a passing surprise. He felt sure that the Dlukus had bound him to the monster’s back, and wondered that beings so low in the evolutionary scale should have been intelligent enough to know the use of thongs. Their act showed a certain power of calculation, as well as a devilish cruelty. It was obvious that they had abandoned him deliberately to an awful doom.

However, he had little time for reflection. The heat-lizard, with an indescribable darting and running motion, went swiftly onward into the dreadful hell of writhing steam and heated rock. The great ball of intolerable whiteness seemed to rise higher momently and to pour its beams upon Howard like the flood of an opened furnace. The horny mail of the monster was like a hot gridiron beneath him, scorching through his clothes; and his wrists and neck and ankles were seared by the tough leather cords as he struggled madly and uselessly against them.

Turning his head from side to side, he saw dimly the horned rocks that leaned toward him from curtains of hellish mist. His head swam deliriously, and the very blood appeared to simmer in his veins. He lapsed at intervals into deadly faintness: a black shroud seemed to fall upon him, but his vague senses were still oppressed by the crushing, searing radiation. He seemed to descend into bottomless gulfs, pursued by unpitying cataracts of fire and seas of molten heat. The darkness of his swoon was turned to immitigable light.

At times, Howard came back to full consciousness, and was forced to grit his teeth to avoid screaming with agony. His eyelids seemed to scorch his eyes, as he blinked in the blinding refraction; and he saw his surroundings in broken glimpses, through turning wheels of fire and blots of torrid color, like scenes from a mad kaleidoscope.

The heat-lizard was following a tortuous stream that ran in hissing rapids, among twisted crags and chasm-riven scarps. Rising in sheets and columns, the steam of the angry water was blown at intervals toward the earth-man, scalding his bare face and hands. The thongs cut into his flesh intolerably, when the monster leapt across mighty fissures that had been made by the cracking of the super-heated stone.

Howard’s brain seemed to broil in his head, and his blood was a fiery torrent in his roasted body. He fought for breath—and the breath seared his lungs. The vapors eddied about him in deepening swirls, and he heard a muffled roaring whose cause he could not determine. He became aware that the heat-lizard had paused; and moving his head a little, saw that it was standing on the rocky verge of a great gulf, into which the waters fell to an unknown depth, amid curtains of steam.