Trella feared she was in for trouble even before Motwick’s head dropped forward on his arms in a drunken stupor. The two evil-looking men at the table nearby had been watching her surreptitiously, and now they shifted restlessly in their chairs.

Trella had not wanted to come to the Golden Satellite. It was a squalid saloon in the rougher section of Jupiter’s View, the terrestrial dome-colony on Ganymede. Motwick, already drunk, had insisted.

A woman could not possibly make her way through these streets alone to the better section of town, especially one clad in a silvery evening dress. Her only hope was that this place had a telephone. Perhaps she could call one of Motwick’s friends; she had no one on Ganymede she could call a real friend herself.

Tentatively, she pushed her chair back from the table and arose. She had to brush close by the other table to get to the bar. As she did, the dark, slick-haired man reached out and grabbed her around the waist with a steely arm.

Trella swung with her whole body, and slapped him so hard he nearly fell from his chair. As she walked swiftly toward the bar, he leaped up to follow her.

There were only two other people in the Golden Satellite: the fat, mustached bartender and a short, square-built man at the bar. The latter swung around at the pistol-like report of her slap, and she saw that, though no more than four and a half feet tall, he was as heavily muscled as a lion.

His face was clean and open, with close-cropped blond hair and honest blue eyes. She ran to him.

“Help me!” she cried. “Please help me!”

He began to back away from her.

“I can’t,” he muttered in a deep voice. “I can’t help you. I can’t do anything.”

The dark man was at her heels. In desperation, she dodged around the short man and took refuge behind him. Her protector was obviously unwilling, but the dark man, faced with his massiveness, took no chances. He stopped and shouted:

“Kregg!”

The other man at the table arose, ponderously, and lumbered toward them. He was immense, at least six and a half feet tall, with a brutal, vacant face.

Evading her attempts to stay behind him, the squat man began to move down the bar away from the approaching Kregg. The dark man moved in on Trella again as Kregg overtook his quarry and swung a huge fist like a sledgehammer.

Exactly what happened, Trella wasn’t sure. She had the impression that Kregg’s fist connected squarely with the short man’s chin before he dodged to one side in a movement so fast it was a blur. But that couldn’t have been, because the short man wasn’t moved by that blow that would have felled a steer, and Kregg roared in pain, grabbing his injured fist.

“The bar!” yelled Kregg. “I hit the damn bar!”

At this juncture, the bartender took a hand. Leaning far over the bar, he swung a full bottle in a complete arc. It smashed on Kregg’s head, splashing the floor with liquor, and Kregg sank stunned to his knees. The dark man, who had grabbed Trella’s arm, released her and ran for the door.

Moving agilely around the end of the bar, the bartender stood over Kregg, holding the jagged-edged bottleneck in his hand menacingly.

“Get out!” rumbled the bartender. “I’ll have no coppers raiding my place for the likes of you!”

Kregg stumbled to his feet and staggered out. Trella ran to the unconscious Motwick’s side.

“That means you, too, lady,” said the bartender beside her. “You and your boy friend get out of here. You oughtn’t to have come here in the first place.”

“May I help you, Miss?” asked a deep, resonant voice behind her.

She straightened from her anxious examination of Motwick. The squat man was standing there, an apologetic look on his face.

She looked contemptuously at the massive muscles whose help had been denied her. Her arm ached where the dark man had grasped it. The broad face before her was not unhandsome, and the blue eyes were disconcertingly direct, but she despised him for a coward.

“I’m sorry I couldn’t fight those men for you, Miss, but I just couldn’t,” he said miserably, as though reading her thoughts. “But no one will bother you on the street if I’m with you.”

“A lot of protection you’d be if they did!” she snapped. “But I’m desperate. You can carry him to the Stellar Hotel for me.”

The gravity of Ganymede was hardly more than that of Earth’s moon, but the way the man picked up the limp Motwick with one hand and tossed him over a shoulder was startling: as though he lifted a feather pillow. He followed Trella out the door of the Golden Satellite and fell in step beside her. Immediately she was grateful for his presence. The dimly lighted street was not crowded, but she didn’t like the looks of the men she saw.

The transparent dome of Jupiter’s View was faintly visible in the reflected night lights of the colonial city, but the lights were overwhelmed by the giant, vari-colored disc of Jupiter itself, riding high in the sky.

“I’m Quest Mansard, Miss,” said her companion. “I’m just in from Jupiter.”

“I’m Trella Nuspar,” she said, favoring him with a green-eyed glance. “You mean Io, don’t you--or Moon Five?”

“No,” he said, grinning at her. He had an engaging grin, with even white teeth. “I meant Jupiter.”

“You’re lying,” she said flatly. “No one has ever landed on Jupiter. It would be impossible to blast off again.”

“My parents landed on Jupiter, and I blasted off from it,” he said soberly. “I was born there. Have you ever heard of Dr. Eriklund Mansard?”

“I certainly have,” she said, her interest taking a sudden upward turn. “He developed the surgiscope, didn’t he? But his ship was drawn into Jupiter and lost.”

“It was drawn into Jupiter, but he landed it successfully,” said Quest. “He and my mother lived on Jupiter until the oxygen equipment wore out at last. I was born and brought up there, and I was finally able to build a small rocket with a powerful enough drive to clear the planet.”

She looked at him. He was short, half a head shorter than she, but broad and powerful as a man might be who had grown up in heavy gravity. He trod the street with a light, controlled step, seeming to deliberately hold himself down.

“If Dr. Mansard succeeded in landing on Jupiter, why didn’t anyone ever hear from him again?” she demanded.

“Because,” said Quest, “his radio was sabotaged, just as his ship’s drive was.”

“Jupiter strength,” she murmured, looking him over coolly. “You wear Motwick on your shoulder like a scarf. But you couldn’t bring yourself to help a woman against two thugs.”

He flushed.

“I’m sorry,” he said. “That’s something I couldn’t help.”

“Why not?”

“I don’t know. It’s not that I’m afraid, but there’s something in me that makes me back away from the prospect of fighting anyone.”

Trella sighed. Cowardice was a state of mind. It was peculiarly inappropriate, but not unbelievable, that the strongest and most agile man on Ganymede should be a coward. Well, she thought with a rush of sympathy, he couldn’t help being what he was.

They had reached the more brightly lighted section of the city now. Trella could get a cab from here, but the Stellar Hotel wasn’t far. They walked on.

Trella had the desk clerk call a cab to deliver the unconscious Motwick to his home. She and Quest had a late sandwich in the coffee shop.

“I landed here only a week ago,” he told her, his eyes frankly admiring her honey-colored hair and comely face. “I’m heading for Earth on the next spaceship.”

“We’ll be traveling companions, then,” she said. “I’m going back on that ship, too.”

For some reason she decided against telling him that the assignment on which she had come to the Jupiter system was to gather his own father’s notebooks and take them back to Earth.

Motwick was an irresponsible playboy whom Trella had known briefly on Earth, and Trella was glad to dispense with his company for the remaining three weeks before the spaceship blasted off. She found herself enjoying the steadier companionship of Quest.

As a matter of fact, she found herself enjoying his companionship more than she intended to. She found herself falling in love with him.

Now this did not suit her at all. Trella had always liked her men tall and dark. She had determined that when she married it would be to a curly-haired six-footer.

She was not at all happy about being so strongly attracted to a man several inches shorter than she. She was particularly unhappy about feeling drawn to a man who was a coward.

The ship that they boarded on Moon Nine was one of the newer ships that could attain a hundred-mile-per-second velocity and take a hyperbolic path to Earth, but it would still require fifty-four days to make the trip. So Trella was delighted to find that the ship was the Cometfire and its skipper was her old friend, dark-eyed, curly-haired Jakdane Gille.

“Jakdane,” she said, flirting with him with her eyes as in days gone by, “I need a chaperon this trip, and you’re ideal for the job.”

“I never thought of myself in quite that light, but maybe I’m getting old,” he answered, laughing. “What’s your trouble, Trella?”

“I’m in love with that huge chunk of man who came aboard with me, and I’m not sure I ought to be,” she confessed. “I may need protection against myself till we get to Earth.”

“If it’s to keep you out of another fellow’s clutches, I’m your man,” agreed Jakdane heartily. “I always had a mind to save you for myself. I’ll guarantee you won’t have a moment alone with him the whole trip.”

“You don’t have to be that thorough about it,” she protested hastily. “I want to get a little enjoyment out of being in love. But if I feel myself weakening too much, I’ll holler for help.”

The Cometfire swung around great Jupiter in an opening arc and plummeted ever more swiftly toward the tight circles of the inner planets. There were four crew members and three passengers aboard the ship’s tiny personnel sphere, and Trella was thrown with Quest almost constantly. She enjoyed every minute of it.

She told him only that she was a messenger, sent out to Ganymede to pick up some important papers and take them back to Earth. She was tempted to tell him what the papers were. Her employer had impressed upon her that her mission was confidential, but surely Dom Blessing could not object to Dr. Mansard’s son knowing about it.

All these things had happened before she was born, and she did not know what Dom Blessing’s relation to Dr. Mansard had been, but it must have been very close. She knew that Dr. Mansard had invented the surgiscope.

This was an instrument with a three-dimensional screen as its heart. The screen was a cubical frame in which an apparently solid image was built up of an object under an electron microscope.

The actual cutting instrument of the surgiscope was an ion stream. By operating a tool in the three-dimensional screen, corresponding movements were made by the ion stream on the object under the microscope. The principle was the same as that used in operation of remote control “hands” in atomic laboratories to handle hot material, and with the surgiscope very delicate operations could be performed at the cellular level.

Dr. Mansard and his wife had disappeared into the turbulent atmosphere of Jupiter just after his invention of the surgiscope, and it had been developed by Dom Blessing. Its success had built Spaceway Instruments, Incorporated, which Blessing headed.

Through all these years since Dr. Mansard’s disappearance, Blessing had been searching the Jovian moons for a second, hidden laboratory of Dr. Mansard. When it was found at last, he sent Trella, his most trusted secretary, to Ganymede to bring back to him the notebooks found there.

Blessing would, of course, be happy to learn that a son of Dr. Mansard lived, and would see that he received his rightful share of the inheritance. Because of this, Trella was tempted to tell Quest the good news herself; but she decided against it. It was Blessing’s privilege to do this his own way, and he might not appreciate her meddling.

At midtrip, Trella made a rueful confession to Jakdane.

“It seems I was taking unnecessary precautions when I asked you to be a chaperon,” she said. “I kept waiting for Quest to do something, and when he didn’t I told him I loved him.”

“What did he say?”

“It’s very peculiar,” she said unhappily. “He said he can’t love me. He said he wants to love me and he feels that he should, but there’s something in him that refuses to permit it.”

She expected Jakdane to salve her wounded feelings with a sympathetic pleasantry, but he did not. Instead, he just looked at her very thoughtfully and said no more about the matter.

He explained his attitude after Asrange ran amuck.

Asrange was the third passenger. He was a lean, saturnine individual who said little and kept to himself as much as possible. He was distantly polite in his relations with both crew and other passengers, and never showed the slightest spark of emotion ... until the day Quest squirted coffee on him.

It was one of those accidents that can occur easily in space. The passengers and the two crewmen on that particular waking shift (including Jakdane) were eating lunch on the center-deck. Quest picked up his bulb of coffee, but inadvertently pressed it before he got it to his lips. The coffee squirted all over the front of Asrange’s clean white tunic.