sprang to his feet, his soft suction pads gripping the floor as though preparatory to a spring. Gone was the sanctimonious unction of his former behavior; the ruthless savage glared out of the red eyes, the flattened fingers were twisting and curling.

"You beastly Earthling," he cried in a voice choked with rage, "I'll—"

The Chief intervened swiftly. "Here, none of that," he said sharply to Miro. "Don't say anything you'll regret later." Then he turned to Grant, who was steadily holding his ground: "There was no reason, Pemberton, to insult an inspector of the Service. Consider yourself reprimanded." But the edge of the rebuke was taken off by the slight twinkle in the Chief's eye.

Somehow a truce was patched up. Grant was to ship as an ordinary passenger on the Althea, the great passenger liner that plied between Callisto and the Earth. It was not his duty to prevent the disappearance of the vessel, the Chief insisted, but to endeavor to discover the cause. It was up to Grant then to escape, if he could, and to report to Miro on Ganymede immediately with his findings. Miro was leaving by his private Service flier at once for Ganymede, to await him. Grant thought he saw a faint sardonic gleam in the Inspector's eyes at that, but paid no particular heed to it at the time.

Now, as Grant stood in the corridor of the great space-flier, listening intently for further sounds from his hidden foe, it flashed on him. Miro knew he was on board. It was a Ganymedan who had treacherously attacked him. The puzzle was slowly fitting its pieces together. But the major piece still eluded him. What would happen to the ship?

As he turned to go back to his room, a ripping, tearing, grinding sound came to his startled ears. It was followed by a sudden swishing noise. Grant knew what that meant. A meteor had ripped into the vitals of the space-flier, and the precious air was rushing through the fissure into outer space. He whirled without an instant's hesitation and sprang down the long corridor toward the captain's quarters. If caught in time, the hole could be plugged.

Even as he ran, there was another grinding smash, then another, and another. Good Lord, they must have headed right into a meteor shower. Panels were sliding open, and people, scantily attired, thrust startled heads out into the corridor. Someone called after him, but he did not heed or stop his headlong race. He must get to the control room at once.

Already the air in the corridor was a sucking whirlpool that beat and eddied about him in its mad rush to escape. It sounded like the drumbeat of unsilenced exploders. A meteor shower of unprecedented proportions! In the back of Grant's mind as he ran, hammered a thought. Every swarm of meteors in the solar system was carefully plotted. The lanes of travel were routed to avoid them. There was no known shower in this particular area!

He collided violently with a strange ungainly figure. In his desperate haste he did not give much heed, but tried to push his way past. The figure turned on him, and then Grant stopped short, an exclamation frozen to his lips. Red unwinking eyes stared out at him from goggles set in a helmet. The body was completely inclosed in lusterless creatoid. It was a Ganymedan in a space-suit!

Grant saw the quick movement of the other toward an open side flap. He did not hesitate an instant. His fist shot out and caught the Ganymedan flush in the throat, while his left hand simultaneously seized the creatoid-covered arm that gripped a pencil-ray. The helmeted head went back with a sickening thud. But the Ganymedan was a powerful brute. Even as he staggered back from the force of the blow, vainly trying to release the pencil-ray for action, his right foot jerked forward. The next moment both were rolling on the floor, twisting and heaving in silent combat. Frightened passengers rushed down the corridor, screaming with terror, half carried along by the hurricane wind, clambering over the combatants in an insane desire to get away, where, they knew not; and still neither relaxed his grip, seeking a mortal hold.

Pemberton was certain that his silent unknown foe held the clue to the mystery he was trying to fathom. He fought on, silently, grimly. The cold creatoid fabric was slippery, but a sudden jerk of an arm, a certain quick twist that Grant was familiar with, and his enemy went limp. Grant's breath was coming in quick, labored gasps. There was very little air left now. But he did not care. He tugged at the fastenings on the helmet. He must see who his captive was, wrest from him the heart of the mystery.

There came a clatter of feet behind him, a sudden rush of space-suited figures that overwhelmed and passed over him with trampling strides. He was torn loose from his prey, rolled over and over, gasping for air. When he staggered to his feet again, bruised and shaken, the corridor was swept clean of figures. His assailants had carried his opponent away with them.

A wild surge of anger swept through him. More Ganymedans, these rescuers, all accoutered for airless space. They had been carefully prepared for this. Heedless of all else, he swayed groggily after them, intent only on joining battle once again. The illumination was dim now, the cries of fear that had rung through the ship were gone; only a deathly silence reigned now. His lungs were burning for want of air; even the whirlwind had died down for lack of fuel. But still he kept on, like a bloodhound on the trail.

He rounded a corner. A slight figure, swaying like a reed, collided with him and would have fallen if he had not thrust out a supporting arm. It was a girl. Even in the shadowy light he saw that she was beautiful. Her delicately molded features were drained white, but her deep pooled eyes were level in their gaze, unafraid.

"I'm sorry," he managed, finding utterance labored, "Are you hurt?"

"Quite all right," she said, with a wan smile, "if only I had some air to breathe."

The essential bravery of her touched him. He forgot all about the escaped Ganymedans.

"We'll have to try some other portion of the ship. Maybe some of the bulkheads are uninjured."

She shook her head. "I just saw the captain," she enunciated faintly. "Every bulkhead is riddled. Said—I—should get space-suit—in stateroom—though no use—doomed. Something wrong—wireless—not working...." Her voice trailed. She had fainted.

Grant caught up her slight form and lurched unsteadily into the nearest cabin. The blood was roaring in his ears now, his heart was pumping madly, but he forced himself on. His eyes strained toward the compartment where the emergency space-suit was neatly compacted. Thank God. It was still there. The inmate had evidently rushed out at the first alarm to join the terror-maddened crush.

Pemberton worked with feverish haste. Somehow he thrust the unconscious girl into the suit, tightened the helmet into position, opened the valve that started the steady measured flow of life-giving oxygen. Then, with dark spots dancing before his eyes, he deposited her gently on the floor, and managed to force himself in the now almost total darkness toward another room.

His swelling hands fumbled. The compartment was empty. Despairing, conscious only of a desire to lie down, to rest, he tried another. It, too, was empty. He stumbled over sprawled bodies, fell, managed to get up again. Again he fumbled into a compartment. The clammy feel of the creatoid never was more welcome. His breath was coming in whistling gasps. It seemed ages of strangulation before the first cool rush of oxygen expanded his tortured lungs. For a full minute he stood there, inhaling deep draughts. Then once more he was himself, his brain functioning with keen clarity.

He must find the Ganymedans and come to grips with them. There was no doubt in his mind that somehow they had been