Phil Hanley came out of the managing editor's office and strode savagely to his desk in the paper littered city room. It was one P.M., between editions, and the reporters and copy-desk men of the Martian Globe were taking things easy for the moment. Hanley slumped into his chair, kicked his feet up on his auto-typewriter, and mouthed an oath.
"He can't do it," he growled. "Who the hell does he think I am anyway? I'll quit, that's what I'll do."

"Not again," taunted McFee, a rewrite man.

"Yes, again," snarled Hanley. "And this time I mean it. Do you know what that lopsided jackass wants me to do? Get a personal interview with the Nebula. For all I know, the Nebula might be a four dimensional robot."

McFee lit a cigarette and leaned against the desk. "Did the old man really hand you that for an assignment?"

Hanley nodded, his anger passing now into glumness. "It's a compliment, I suppose," he said, "for anyone to think I might have even a chance."
His eyes turned from the room and stared unseeing through the window into the metropolitan area of Crater City.

"The Nebula," he said slowly. "Every dick and I.P. man in the System has been tearing his hair, trying to get a lead on who or what he is.
The Nebula! The greatest cracksman of all time!"

McFee exhaled a lungful of smoke. "He's quite a guy, isn't he?"

Deliberately Hanley dropped his feet to the floor and sat erect.
"Listen," he said, "he's the Robin Hood of the day, if you can possibly remember your ancient history. Two years ago he swiped the electrolic jewels from the atomic motors of the Fortuna, the gambling space ship, broke them into two hundred parts and gave them to the Society for Orphaned Children. A year ago he entered the inner rooms of the Venus Gallery and made off with the Cosmic Lady, the greatest painting of the age.

"The man's a wizard. No vault door, no lock mechanism keeps him out.
He walks in, takes what he wants, and leaves before the I.P. men know what's happened. All they find is that little pastel-blue card with the cluster of white dots in the shape of the Constellation Orion. That's what gave him the name of the Nebula, you see."

McFee nodded. "I know," he said, "but who is he? And what's his permanent address?"

For a moment Hanley said nothing. He reached in his pocket, drew out a bulldog pipe and a worn tobacco pouch. A glitter was slowly entering his eyes. "You know," he said, "I have half a mind to try and find out at that."

The mercury clock over the white mantel chimed the hour of eight A.M., and Jimmy Starr sat up in bed yawning. As the last note faded into silence, the door of the room opened, and a white-haired man entered, carrying a tray.

"Good morning, Mr. Starr."

"Good morning, Peters," Jimmy said. "Did you bring the paper?"

The servant nodded, propped a morning edition against Jimmy's upraised knees and placed the breakfast tray on the side of the bed. "Will you have orange juice or Martian melon today?" he asked.

"Orange juice, I believe," replied Jimmy absently, and then coughed to hide the sudden tenseness that had entered his voice. He waited impatiently while the aged servant opened the window blinds and busied himself about the room.

When at last the man had gone, Jimmy sat bolt upright and stared at the screaming type.

NEBULA ON THE LOOSE AGAIN
GENTLEMAN BURGLAR PROVES
TO BE COMMON CRIMINAL

The running story was bitter in its denunciation. Where before those same columns had accepted each new exploit of the Nebula as a prank upon the police and an irritation to the wealthy, they now demanded legal action. For this time the Nebula had committed murder!

The Crater City Museum had been robbed during the night. Three priceless Thro-Pahl figurines had been stolen. An aged night watchman had been brutally beaten to death.

"The guilt is undeniable," the paper continued. "Drunk with power, this sadist had the effrontery to leave behind one of his mocking cards.
What are the police going to do about it?"

Jimmy Starr leaned back and let a soft whistle escape from his lips.
The newspaper story was all wrong. For Jimmy Starr had spent the entire night in his apartment. And Jimmy Starr was the Nebula!

He didn't know quite how long he had been playing this dual role.
Years now, ever since his father, Randall Starr, president of the Triplanetary Freight Lines had been murdered and had left his enormous fortune to his son.

Randall Starr had come up from poverty with his only heritage, a brilliant mind and skillful hands. He had dabbled in a little of everything before he had become associated with the Venus-Mars-Earth shipping business. But all during his years of executive activity, he had always found time for two things: his hobby, the manufacture and study of theft-proof materials and devices; and the deciphering of the ancient Lost Chronicles of Mars.

It was this last that had resulted in his untimely end. Jimmy Starr had known for a long time that his father was on the verge of a great discovery, but what that discovery was he had had no inkling.

"Wait 'til I've finished," Randall Starr would always say when questioned. "Some day I'll have an announcement to make that will startle all Mars."

And then one night Jimmy Starr had been wakened by a terrific crash downstairs in the lower-floor study. He had rushed to the room to find his father stretched out on the floor, blood trickling from a gaping wound in his head. The window was open, showing the way of the assailant's escape. Randall Starr's filing cabinet had been thrown to the floor and battered open with some heavy instrument. Papers lay strewn about in wild disorder.

Jimmy knelt at his father's side, in time to hear the old man's last gasping words. "The ... Chronicles ... they took ... the five cyphers.
You must get them back, Jimmy, before the last one is completed and the secret discovered. You must, do you understand? The future of all life on this planet depends on it."

"Who...?" choked Jimmy. "Tell me who, and I'll...."

But the effort had been too great. The old man fell back, his warning unfinished.

Clues? Jimmy had employed the finest detectives on Mars in a vain attempt to track down the guilty one. He had followed trails himself, questioned all of his father's former friends and associates. The one and only shred of evidence he had led him no place. This was a polished falpa button which Randall Starr had torn from his assailant's tunic during the struggle—the type of button which members of the limited superiors class effected. The superiors were a throw-back to the feudalistic days of a by-gone age. Powerful overlords with inherited political and financial power, they still wielded a strong influence over an otherwise partially modernized society.

So this much Jimmy knew—his father had been murdered and the Chronicles cypher taken by a man who walked in the highest brackets of the System's social worlds.

In time Jimmy's grief passed, and he began to follow in his father's footsteps. Theoretically, he was acting head of Triplanetary. But with the shipping line operating smoothly with hundreds of efficient under-officials, there was little for him to do. After graduating from the Martian School of Technology, he toured the System in his own space-yacht. It was that trip that brought home to him the poverty and sordid conditions existent in the various worlds.

On Venus he had seen powerful land-owners growing fat and rich while native Kamalis and Sarakans toiled in the swamps. On Mars he had toured the luxurious plaisances and estates of the D.O.F.C—the Descendents of the First Colonists—and a hundred miles out in the desert had walked through the stinking narrow streets of the Thedras, the despised aboriginals of the West Plateaus.

Then and there Jimmy Starr had decided to add a twofold purpose to his life. He would do all in his power to aid the oppressed poor, and he would strain every effort to plague the lives of the superiors class.
Some day, in some way, that effort would lead him, he felt sure, to his father's murderer and the stolen Chronicles cypher. The only item in question was the time element.

He spent six months in his father's private library, studying everything he could find on locks, time vaults, hermetic chambers and impenetrable walls. Six months more went into a thorough reading on the various subjects of criminology, micro-fingerprints, robot detectors.

He had begun quietly at first, a small art treasure taken from the collection of some greedy superiors millionaire. But gradually the daring of those thefts, the absolute lack of clues, with the exception of the tell-tale blue card, had attracted attention. In a year his fame had spread as far as Pluto. In six months more the Nebula was a byword in every tongue.

The police had sworn action, the press had chuckled, and the public had looked with open admiration on this benefactor of the downtrodden.

Now all that was over. The Nebula was a criminal. He was accused of murder.

Slowly Jimmy Starr got out of bed and began to dress. Funny, he had never thought of this contingency. Someone had seen an opportunity to profit by his name, and had utilized it with cold-blooded efficiency.

He lit a cheroot and stood there smoking. A bell tinkled behind him, announcing a call on the visiphone. He crossed to the panel, touched a stud. A voice came out of the speaker, but no image appeared on the vision screen.

"Good morning, Nebula!"

An electric shock swept through him. His cheroot slipped from his fingers.

"Good morning, Nebula. Answer please."

Mechanically Jimmy's fingers found the transmitting button and clicked it over. But he stood out of range of the vision screen as he replied, "Who's speaking?"

The feminine voice, sweet and musical, laughed gaily. "I'm sorry I can't tell you that. You may call me Andromeda, if you will. Now listen closely, Jimmy Starr. I know your secret. I know that you live a dual life, that you are that much sought after gentleman cracksman, the Nebula."

The voice laughed again, but there was no mockery in it. "You needn't be afraid, Jimmy, I'm not going to let the cat out of the bag. But I will, unless you agree to follow my orders. Is that clear?"

For a long moment Jimmy stood there in silence.

"Never mind," the voice continued, "I didn't expect you to admit it.
But listen. The Nebula is no longer a champion of the poor. In the eyes of the press and the police, he has committed murder. I know that you are innocent of that charge. It is now eight-thirty. In exactly fifteen hours you will go to the central offices of the Crater City Trust Company at Ninth and Planet. You will enter in any way you see fit, open the vault and take from the compartment marked W-203 the three articles it contains. Do you understand? Compartment W-203."

There was a click and the visiphone was silent.

Frantically Jimmy twisted the control switch on and off. "Hello," he said, "hello!"

He turned slowly to face the looking glass on the opposite wall mirrored the sudden haggardness that had entered his features. In half an hour his entire world had crashed. His identity was known. He was wanted for a foul crime.

Yes, he had been hunted before, but now the police and the I.P. men would leave no stone unturned in their efforts to capture him. His pursuers would be relentless.

He paced to the window and looked down on the Martian city. To the east where the main sky ramp led to the city's space port lay the huge ditch that was the beginning of Canal Grand. Like a crayon smear on a piece of cardboard, it stretched off into the desert, bleak and desolate.

At fifteen minutes past eleven that night Jimmy Starr opened a panel in his room and took his place in a cylindrical shell, touched a control and settled back. Save for a slight jar and an audible hum, there was no sensation of movement. Moments later the tube-cage jarred again, the door slid open, and he climbed out on a small lighted kiosk in the center of a well of darkness. A narrow ramp led upward, and he made his way to the street level in a few quick strides.

He now stood on the intersection of Ninth and Planet.

Jimmy Starr sauntered across the street, studying each passerby out of the corner of his eyes. Before the entrance of the Crater City Trust Company he paused to light a cheroot. He stood there, smoking quietly while a turbaned Kagor from the North Desert Country shuffled by, dragging his cumbersome third leg after him.

Then he slipped open his tunic, exposing a small compact carry-case strapped about his middle. Opening it, he selected from its array of objects a slender metal tube, capped at one end. To this he quickly fastened a small ball of hardened carponium clay. He unscrewed a cap in the clay ball and inserted a small pellet.

With flying fingers, he shoved the tube hard against the door lock.
That lock was not the best, but it was one of the most dependable theft-proof devices on the market.

Mentally he counted the seconds as each pulsation within the tube was transmitted to his hand. At the tenth he stiffened. There was a dull thud, a little puff of smoke, and a grating and jangling as of breaking glass.

Then he was inside, pacing down the center aisle of the main office.
He had no need for a torch. The place was brilliantly lighted with overhead carboliers, and he knew that he was clearly visible from the street.

In rapid strides he reached the far end of the office, where an enormous vault door of arelium steel was imbedded in a frame of kartite. That frame was anchored in natural rock piers ninety feet below. The entire structure was as impregnable as human intellect could make it.

Jimmy Starr leaped over the low railing that separated the vault from the office proper. Again he opened the little carry-case and from a lower compartment took out a tightly rolled Martian papyrus.

He was working fast now, putting into action a plan that he had formed on his visit to this office earlier in the day. Then, while he had stood discussing the financial status of Triplanetary Shipping with one of the Trust Company officials, he had managed to slip out a tiny camera and, unobserved, take a quick photograph of the rear wall of the office.

Back in his own apartment it had been the work of a few moments to transfer the scene on the negative onto this elastic papyrus.

He stood up on the railing, fastened the two ends of the papyrus to the side wall; then, utilizing all his strength, stretched it across the full width of the office to the opposite wall.

Finished, he slipped behind the screen with a gay laugh. Let a passerby gaze in the street window now. He would see a deserted office with the unmolested vault in clear view. From the street no one could know that vault was an enlarged photograph on a screen, and that behind that screen crouched the most wanted cracksman on Mars—the Nebula!

He spent a moment surveying the massive vault. "Craig-Orlan, Series A.
Model Four," he muttered appreciatively. "Mercury time lock, rondulated tumblers, protected with individual micacaps. This is going to be tough."

He took from the carry-case a pair of earphones, snapped them on and pressed their connection to the panel just below the main dial. Slowly he began to turn that dial, straining his ears for tell-tale clicks.

The silence of the office pressed down upon him. Far off sounded the hollow roar as the night Earth Express blasted down to its cradle.

For several minutes he continued. Then his brow furrowed in a frown.
"Must have a shield of some kind behind it," he muttered. He opened the carry-case again, drew forth a tiny electrolic drill with a wedge-shaped bit. A low hum sounded as he switched the drill on and pressed it against the panel.

When an aperture of half an inch in depth had been bored, he removed the drill and placed in the opening another of his pellets. Ten seconds and the puff of blue smoke. Once more he slipped on the headphones.

This time a smile of satisfaction turned his lips. In the receivers he could hear distinctly each metallic click as the grooved tumblers fell into position. He reached up now and shoved a huge kapar bar far over in its slot. On silent hinges the enormous vault door began to open.

But this was only the beginning. It was a full hour before he had penetrated the second and third inner doors of the vault, another half hour before he located in the vast array of files, Compartment W-203.

About to open it, he stood motionless in thought. What was he doing here? Why was he ransacking the vault of the Crater City Trust, one of the most respected and ethical financial institutions in the city? He wanted nothing of theirs. More than that, there was a murder charge on his head, and he was deliberately taking chances when all logic screamed at him to hide.

As in a dream he heard that musical voice that had come over the visiphone, "Listen, Jimmy Starr, I know your secret...." He inserted a false key in the file lock and opened it.

Nothing! The compartment was empty.

A wave of bitterness swept over him. He thrust the compartment shut savagely and turned to leave the vault. Half way he halted in mid-stride.

A sound had reached his ears from the opposite side of the papyrus screen, the sound of someone fumbling with the latch of the front entrance door.

Quickly Jimmy passed through the three doors of the vault. He paused before the combination to slide a small card under the dial.
Pastel-blue in color, that card bore the design of the constellation Orion.

Then he reached up, whipped down the papyrus screen and crouched back of the railing. The man at the front entrance had discovered the broken lock; the door crashed open; excited footsteps pounded inward.

Bending low, Jimmy darted down the side aisle, keeping his head well below the top of the desks. Once he shot a look at the intruder. It was Hamilton Garth, president of Crater City Trust! A gray-haired man with a wiry build, an iron visage, and heavy-browed gimlet eyes. Before the yawning door of the vault Garth stopped short and uttered a cry of consternation. He spun on his heel and with rapid strides made for the door.

But not before Jimmy had reached it. He raced through the entrance just as Garth sighted him and gave a hoarse shout.

Jimmy raced down the street a hundred yards, then hurled himself into an alley. A police officer was running toward him, attracted by Garth's cries.

Even as Jimmy crouched there, new sounds added to the confusion. The alarm tocsin of the Crater City Trust shrilled up and up into the rarified air. Far down the street the answering siren of the I.P. depot rose in deafening crescendo. Jimmy could hear windows bang open in the buildings across the thoroughfare. The emergency street lamps flared on, turning the intersection into a stage of ghastly white.

The alley-way in which he crouched was a dead-end. Jimmy thrust aside the wave of helplessness that swept over him and steeled himself for action. The Nebula couldn't be caught. Not now with brutality dogging his footsteps.

With a swift movement he whipped off the tunic, threw it from him.
Frantically he opened the carry-case and took from it a short collapsible rod, a folded rakish evening cap. He shoved the carry-case under his waist coat, hoping that the bulge would not be detected, set the cap on his head at a jaunty angle and jerked the rod out to its full four feet.

That rod was an explosive detonator for use on time doors when all other means of entrance failed. But it was a cane now. Swinging it, Jimmy darted out into the glare of the street, then began to pace leisurely forward straight in the direction of Crater City Trust.

When he reached the entrance, a small crowd had gathered, and Hamilton Garth was in their midst excitedly talking to an I.P. officer.

"Vault doors wide open!" he was shouting. "Second and third doors, too! It's the Nebula! I saw his card. Why the devil don't you do something?"

The I.P. man was taking notes in a little book. "Calm yourself, Mr.
Garth," he said. "Whoever broke in here can't get away this time. The impenetration walls have automatically closed down. The entire area is cut off by a ring of steel."

"But it's the Nebula I tell you, you stupid fool!" cried Garth.
"While you stand there like an idiot—" The eyes of the Trust Company president suddenly fastened on Jimmy, leaning comfortably on his rod-cane at the edge of the growing crowd. "Mr. Starr, I'm certainly glad to see you. Help me. Tell me what I should do...."

Nodding quietly, Jimmy stepped forward. To the I.P. he said casually, "J. C. Starr, president of Triplanetary Shipping. How much has been stolen, officer?"

Another I.P. man emerged from the Trust office. "Only one compartment opened, sir. W-203."

Hamilton Garth looked bewildered. "That's odd," he said. "The W series of files are all unused. There's nothing in any of them."

Jimmy laughed. "Mr. Garth, you can consider yourself a lucky man. The Nebula seems to have muffed things this time. Good night."

He turned and sauntered off down the street.

It was the following morning, and for an hour Jimmy Starr had sat by the visiphone in his room, waiting for a call. A tray of half-smoked cheroots lay on the table beside the instrument.

The bell sounded. Jimmy touched the stud.

"Good morning, Nebula. We failed last night, didn't we?"

He leaned back in his chair and smiled. Though that haunting musical voice stirred him deeply, he had full control of himself now. For an hour he had been preparing mentally what he would say.

"Young woman," he said, "or Andromeda, as you choose to call yourself, I haven't the slightest idea of what you're talking about. Yesterday you made a connection with my instrument and hung up without revealing your image. My name is James C. Starr, and if you wish to converse with me, I suggest you show yourself. Otherwise...."

"Wait!" The gayness left the unseen girl's voice. "Wait, don't touch that stud. We failed last night, Jimmy Starr. But we can't fail again tonight. Everything is at stake. Do you understand, everything. The very future of life here on Mars. Jimmy, what do you know about the canals?"

"The canals?" He forgot his protestations to consider thoughtfully.
"Why nothing much. They're to be opened and filled with water in a year. Everyone knows that. So far the locks have been giving the engineers a little trouble, but...."

"Not a little trouble, Jimmy. A whole lot of trouble. At the present time specifications call for a hundred and twelve locks and sub power stations down the length of Canal Grand alone. And there are seven hundred and eight subsidiary canals branching into the main stem.
Add to those figures the number of lesser canals branching into the subsidiary canals, the necessary freight and passenger depots, and you can see what a tremendous engineering project it will be."

"It can be done," Jimmy said confidently.

"It can, yes, if the engineers locate a new deposit of pxar, the part organic, part inorganic material that alone will withstand the terrible refraction-rot of the red desert country."

Jimmy didn't know what she was driving at, but what she said was true.
Refraction-rot, the multiple infra-red light radiations from the scarlet sands of the desert played hob with all kinds of construction work. Pxar alone had the resiliency and the hardness to withstand the terrible disintegration processes of the shifting sands. And there was very little pxar left.

The voice continued:

"Jimmy, I can't tell you everything yet. But I can tell you this. By joining forces with me, you will be working toward the recovery of your father's lost secret and the identification of the man who murdered him.

"Tonight at midnight you will enter the offices of Phobos Enterprises and take from their vault the paper-wrapped box on the third shelf.
Good luck, Nebula."

Phil Hanley, reporter of the Globe, let himself into his apartment, strode straight to the liquor cabinet and took a stiff drink. Then he sat down before a table and spread an array of objects before him.

They were a curious collection: A polished falpa button of the type affected by members of the superiors class; two panelled cards, each with the design of the Constellation Orion, two rather blurred photographs of finger prints, and a notebook.

These findings were the results of Hanley's activities during the night. Still obsessed with his plan to get a signed interview with the Nebula, he had reasoned, logically enough, that the only way to do so was to learn first the cracksman's identity.

The button first. It was elliptical in shape and bore that curious triangular emblem so hated by the poorer classes. Hanley had found it on the office floor of the Crater City Trust Company. He realized, however, that any number of superiors might have business with that establishment and that the button's presence there meant nothing.

In rotation he examined the two panelled cards and the fingerprint photographs. He brought a powerful atolight down and studied them with the aid of a proberglass.

At

Enter the Nebula