Special Investigator Billy Neville was annoyed, and for more reasons than one. He had just done a tedious year in the jungles of Venus stamping out the gooroo racket and then, on his way home to a well-deserved leave and rest, had been diverted to Mars for a swift clean-up of the diamond-mine robbery ring. And now, when he again thought he would be free for a while, he found himself shunted to little Pallas, capital of the Asteroid Confederation. But clever, patient Colonel Frawley, commandant of all the Interplanetary Police in the belt, merely smiled indulgently while Neville blew off his steam.

"You say," said Neville, still ruffled, "that there has been a growing wave of blackmail and extortion all over the System, coupled with a dozen or so instances of well-to-do, respectable persons disappearing without a trace. And you say that that has been going on for a couple of years and several hundred of our crack operatives have been working on it, directed by the best brains of the force, and yet haven't got anywhere. And that up to now there have been no such cases develop in the asteroids. Well, what do you want me for? What's the emergency?"

The colonel laughed and dropped the ash from his cigar, preparatory to lying back in his chair and taking another long, soothing drag. The office of the Chief Inspector of the A.C. division of the I.P. was not only well equipped for the work it had to do, but for comfort.

"I am astonished," he remarked, "to hear an experienced policeman indulge in such loose talk. Who said anything about having had the best brains on the job? Or that no progress had been made? Or that there was no emergency? Any bad crime situation is always an emergency, no matter how long it lasts. Which is all the more reason why we have to break it up, and quickly. I tell you, things are becoming very serious. Lifelong partners in business are becoming suspicious and secretive toward each other; husbands and wives are getting jittery and jealous. Nobody knows whom to trust. The most sacred confidences have a way of leaking out. Then they are in the market for the highest bidder. No boy, this thing is a headache. I never had a worse."

"All right, all right," growled Neville, resignedly. "I'm stuck. Shoot! How did it begin, and what do you know?"

The colonel reached into a drawer and pulled out a fat jacket bulging with papers, photostats, and interdepartmental reports.

"It began," he said, "about two years ago, on Io and Callisto. It spread all over the Jovian System and soured Ganymede and Europa. The symptoms were first the disappearances of several prominent citizens, followed by a wave of bankruptcies and suicides on both planetoids. Nobody complained to the police. Then a squad of our New York men picked up a petty chiseler who was trying to gouge the Jovian Corporation's Tellurian office out of a large sum of money on the strength of some damaging documents he possessed relating to a hidden scandal in the life of the New York manager. From that lead, they picked up a half-dozen other small fry extortionists and even managed to grab their higher-up—a sort of middleman who specialized in exploiting secret commercial information and scandalous material about individuals. There the trail stopped. They put him through the mill, but all he would say is that a man approached him with the portfolio, sold him on its value for extortion purposes, and collected in advance. There could be no follow up for the reason that after the first transaction what profits the local gang could make out of the dirty work would be their own."

"Yes," said Neville, "I know the racket. When they handle it that way it's hard to beat. You get any amount of minnows, but the whales get away."

"Right. The disturbing thing about the contents of the portfolio was the immense variety of secrets it contained and that it was evidently prepared by one man. There were, for example, secret industrial formulas evidently stolen for sale to a competitor. The bulk of it was other commercial items, such as secret credit reports, business volume, and the like. But there was a good deal of rather nasty personal stuff, too. It was a gold mine of information for an unscrupulous blackmailer, and every bit of it originated on Callisto. Now, whom do you think, could have been in a position to compile it?"

"The biggest corporation lawyer there, I should guess," said Neville. "Priests and doctors know a lot of personal secrets, but a good lawyer manages to learn most everything."

"Right. Very right. We sent men to Callisto and learned that some months earlier the most prominent lawyer of the place had announced one day he must go over to Io to arrange some contracts. He went to Io, all right, but was never seen again after he stepped out of the ship. It was shortly after, that the wave of Callistan suicides and business failures took place."

"All right," agreed Neville, "so what? It has happened before. Even the big ones go wrong now and then."

"Yes, but wait. That fellow had nothing to go wrong about. He was tremendously successful, rich, happily married, and highly respected for his outstanding integrity. Yet he could hardly have been kidnaped, as there has never been a ransom demand. Nor has there ever been such a demand in any of the other cases similar to it.

"The next case to be partially explained was that of the disappearance of the president of the Jupiter Trust Company at Ionopolis. All the most vital secrets of that bank turned up later in all parts of the civilized system. We nabbed some peddlers, but it was the same story as with the first gang. The facts are all here in this jacket. After a little you can read the whole thing in detail."

"Uh, huh," grunted Neville, "I'm beginning to see. But why me , and why at Pallas?"

"Because you've never worked in the asteroids and are not known here to any but the higher officers. Among other secrets this ring has, are a number of police secrets. That is why setting traps for them is so difficult. I haven't told you that one of their victims seems to have been one of us. That was Jack Sarkins, who was district commander at Patroclus. He received an apparently genuine ethergram one day—and it was in our most secret code—telling him to report to Mars at once. He went off, alone, in his police rocket. He never got there. As to Pallas, the reason you are here is because the place so far is clean. Their system is to work a place just once and never come back. They milk it dry the first time and there is no need to. Since we have no luck tracing them after the crime, we are going to try a plant and wait for the crime to come to it. You are the plant."

"I see," said Neville slowly. He was interested, but not enthusiastic. "Some day, somehow, someone is coming here and in some manner force someone to yield up all the local dirt and then arrange his disappearance. My role is to break it up before it happens. Sweet!"

"You have such a way of putting things, Neville," chuckled the colonel, "but you do get the point."

He rose and pushed the heavy folder toward his new aide.

"Bone this the rest of the afternoon. I'll be back."

It was quite late when Colonel Frawley returned and asked Neville cheerily how he was getting on.

"I have the history," Neville answered, slamming the folder shut, "and a glimmering of what you are shooting at. This guy Simeon Carstairs, I take it, is the local man you have picked as the most likely prospect for your Master Mind crook to work on?"

"He is. He is perfect bait. He is the sole owner of the Radiation Extraction Company which has a secret process that Tellurian Radiant Corporation has made a standing offer of five millions for. He controls the local bank and often sits as magistrate. In addition, he has substantial interests in Vesta and Juno industries. He probably knows more about the asteroids and the people on them than any other living man. Moreover, his present wife is a woman with an unhappy past and who happens also to be related to an extremely wealthy Argentine family. Any ring of extortionists who could worm old Simeon's secrets out of him could write their own ticket."

"So I am to be a sort of private shadow."

"Not a bit of it. I am his bodyguard. We are close friends and lately I have made it a rule to be with him part of the time every day. No, your role is that of observer from the sidelines. I shall introduce you as the traveling representative of the London uniform house that has the police contract. That will explain your presence here and your occasional calls at headquarters. You might sell a few suits of clothes on the side, or at least solicit them. Work that out for yourself."

Neville grimaced. He was not fond of plainclothes work.

"But come, fellow. You've worked hard enough for one day. Go up to my room and get into cits. Then I'll take you over to the town and introduce you around. After that we'll go to a show. The showboat landed about an hour ago."

"Showboat? What the hell is a showboat?"

"I forget," said the colonel, "that your work has been mostly on the heavy planets where they have plenty of good playhouses in the cities. Out here among these little rocks the diversions are brought around periodically and peddled for the night. The showboat, my boy, is a floating theater—a space ship with a stage and an auditorium in it, a troupe of good actors and a cracking fine chorus. This one has been making the rounds quite a while, though it never stopped here before until last year. They say the show this year is even better. It is the "Lunar Follies of 2326," featuring a chorus of two hundred androids and with Lilly Fitzpatrick and Lionel Dustan in the lead. Tonight, for a change, you can relax and enjoy yourself. We can get down to brass tacks tomorrow."

"Thanks, chief," said Neville, grinning from ear to ear. The description of the showboat was music to his ears, for it had been a long time since he had seen a good comedy and he felt the need of relief from his sordid workaday life.

"When you're in your makeup," the colonel added, "come on down and I'll take you over in my copter."

It did not take Billy Neville long to make his transformation to the personality of a clothing drummer. Every special cop had to be an expert at the art of quick shifts of disguise and Neville was rather better than most. Nor did it take long for the little blue copter to whisk them halfway around the knobby little planetoid of Pallas. It eased itself through an airlock into a doomed town, and there the colonel left it with his orderly.

The town itself possessed little interest for Neville though his trained photographic eye missed few of its details. It was much like the smaller doomed settlements on the Moon. He was more interested in meeting the local magnate, whom they found in his office in the Carstairs Building. The colonel made the introductions, during which Neville sized up the man. He was of fair height, stockily built, and had remarkably frank and friendly eyes for a self-made man of the asteroids. Not that there was not a certain hardness about him and a considerable degree of shrewdness, but he lacked the cynical cunning so often displayed by the pioneers of the outer system. Neville noted other details as well—the beginning of a set of triple chins, a little brown mole with three hairs on it alongside his nose, and the way a stray lock of hair kept falling over his left eye.

"Let's go," said the colonel, as soon as the formalities were over.

Neville had to borrow a breathing helmet from Mr. Carstairs, for he had not one of his own and they had to walk from the far portal of the dome across the field to where the showboat lay parked. He thought wryly, as he put it on, that he went from one extreme to another—from Venus, where the air was over-moist, heavy and oppressive from its stagnation, to windy, blustery Mars, and then here, where there was no air at all.

As they approached the grounded ship they saw it was all lit up and throngs of people were approaching from all sides. Flood lamps threw great letters on the side of the silvery hull reading, "Greatest Show of the Void—Come One, Come All—Your Money Back if Not Absolutely Satisfied." They went ahead of the queue, thanks to the prestige of the colonel and the local tycoon, and were instantly admitted. It took but a moment to check their breathers at the helmet room and then the ushers had them in tow.

"See you after the show, Mr. Allington," said the colonel to Neville, "I will be in Mr. Carstairs box."

Neville sank into a seat and watched them go. Then he began to take stock of the playhouse. The seats were comfortable and commodious, evidently having been designed to hold patrons clad in heavy-dust space-suits. The auditorium was almost circular, one semi-circle being taken up by the stage, the other by the tiers of seats. Overhead ranged a row of boxes jutting out above the spectators below. Neville puzzled for a long time over the curtain that shut off the stage. It seemed very unreal, like the shimmer of the aurora, but it affected vision to the extent that the beholder could not say with any certainty what was behind it. It was like looking through a waterfall. Then there was eerie music, too, from an unseen source, flooding the air with queer melodies. People continued to pour in. The house gradually darkened and as it did the volume and wildness of the music rose. Then there was a deep bong, and lights went completely out for a full second. The show was on.

Neville sat back and enjoyed it. He could not have done otherwise, for the sign on the hull had not been an empty plug. It was the best show in the void—or anywhere else, for that matter. A spectral voice that seemed to come from everywhere in the house announced the first number—The Dance of the Wood-sprites of Venus. Instantly little flickers of light appeared throughout the house—a mass of vari-colored fireflies blinking off and on and swirling in dizzy spirals. They steadied and grew, coalesced into blobs of living fire—ruby, dazzling green, ethereal blue and yellow. They swelled and shrank, took on human forms only to abandon them; purple serpentine figures writhed among them, paling to silvery smoke and then expiring as a shower of violet sparks. And throughout was the steady, maddening rhythm of the dance tune, unutterably savage and haunting—a folk dance of the hill tribes of Venus. At last, when the sheer beauty of it began to lull the viewers into a hypnotic trance, there came the shrill blare of massed trumpets and the throb of mighty tom-toms culminating in an ear-shattering discord that broke the spell.

The lights were on. The stage was bare. Neville sat up straighter and looked, blinking. It was as if he were in an abandoned warehouse. And then the scenery began to grow. Yes, grow. Almost imperceptible it was, at first, then more distinct. Nebulous bodies appeared, wisps of smoke. They wavered, took on shape, took on color, took on the appearance of solidity. The scent began to have meaning. Part of the background was a gray cliff undercut with a yawning cave. It was a scene from the Moon, a hangout of the cliffdwellers, those refugees from civilization who chose to live the wild life of the undomed Moon rather than submit to the demands of a more ordered life.

Characters came on. There was a little drama, well conceived and well acted. When it was over, the scene vanished as it had come. A comedy team came out next and this time the appropriate scenery materialized at once as one of them stumbled over an imaginary log and fell on his face. The log was not there when he tripped, but it was there by the time his nose hit the stage, neatly turning the joke on his companion who had started to laugh at his unreasonable fall.

On the show went, one scene swiftly succeeding the next. A song that took the fancy of the crowd was a plaintive ballad. It ran:

There was a ballet in which a witch rode a comet up into the sky, only to turn suddenly into a housewife and sweep all the cobwebs away. The featured stars came on with the chorus, and Lilly Fitzpatrick sang the big hit song, "You're a Big, Bad Nova to Burn Me Up This Way!" Then a novelty quartet appeared, to play on the curious Callistan bourdelangs , those reeds of that planet that grow in bundles. When dried and cut properly, they make multiple-barreled flutes with a tonal quality that makes the senses quiver. The show closed with a grand finale and flooded the house with the Nova song.

It was over. The stage was bare and the shimmering curtain that was not a curtain was back in place. People began to rise and stream into the aisles.

"La-deez and gen-tul-men!"

The voice boomed out and people stopped where they stood. A man in evening clothes had stepped through the curtain and was calling for attention.

"You have seen our regular performance. We hope it has pleased you and you will come again next year. But if you will kindly remain in your seats, the ushers will pass around with tickets for the after-show. We have prepared for your especial delectation a little farce entitled, 'It Happens on Pallas.' Now, ladeez and gen'men, I assure you that this sketch was prepared solely for your entertainment and any resemblance of any character in it to any real person is purely coincidental. It is all in fun, and no offense intended. I thank you."

Billy Neville was bolt upright in his seat by then and his eyes glinted hard through narrow slits. Something had rung the bell in his memory, but he did not know what. He would have sworn he had never seen that announcer before, and yet....

The man stepped backward into the curtain and appeared to vanish. The audience were grinning widely and resuming their seats.

"This is going to be good," said the man next to him as he dug for the required fee. "It is their specialty. It beats the regular show, I think."

Neville paid the usher, too, and sat where he was. He shot a glance upward at the box and saw Mr. Carstairs and the colonel in animated conversation and apparently having a grand time. Presently the ushers had done their work. The hall began to darken and the scenery come up. The scene was the main street of New Athens, as some called Pallas' principal town. Neville relaxed and forgot his recent sudden tension for a moment.

But it was only for a moment. For an instant later he was sitting up straight again, watching the development of the act with cold intentness. For the two main characters were comedy parodies of Mr. Carstairs and Colonel Frawley. At first glance they were Mr. Carstairs and the colonel, but a second look showed it was only an impression. The police inspector's strutting walk was overdone, as were his other mannerisms, and the same was true of the magnate's character. Their makeup was also exaggerated, Mr. Carstair's mole being much enlarged and a great deal made of his plumpness. Yet the takeoff was deliriously funny and the audience rolled with laughter. Neville stole another look upward and could make out that both the subjects of the sketch were grinning broadly.

It was a silly, frothy skit about a dog, a lost dog. It seems that Mr. Carstairs had a dog and it strayed. He asked the police to help him find it and they helped. The inspector brought out the whole force. It was excruciatingly funny, and Neville roared at times along with the rest, though there were many local references that he did not understand, nor did he know some of the minor characters were so splittingly entertaining. The man next to him writhed in spasms of delight and almost strangled at one episode.

"Oh, dear," he managed to gasp, "what a scream ... ho, ho, ho, ho, ... gup! It happened ... just like that ... he did lose a dog and all the cops on Pallas couldn't find it ... oh me, oh my...." Peals of laughter drowned out the rest.

The postlude came to its merry end. This time, the show was over for keeps and the audience began trooping out. Neville got up and looked around for his friend, but the box was empty. So he strolled down the aisle and had a closer look at the illusion of a curtain. He understood some of the effects achieved that night, but the curtain was a new one to him. After standing there a moment he discovered that he could hear voices through it. One was Colonel Frawley's. He was saying:

"Certainly I am not offended. I enjoyed it. I would like to meet the man and congratulate him on the takeoff."

Neville climbed up onto the stage and walked boldly through the curtain. There was a brief tingly feeling, and then he was backstage. Most of the actors had gone to their dressing rooms, but several stood about chatting with the colonel and Mr. Carstairs.

At that moment the man who had made the announcement came on the stage and spoke to Colonel Frawley.

"I dislike interrupting you, Inspector," he said obsequiously, "but one of our patrons is making trouble in the wash-room. She claims her pocket was picked. Would you come?"

"Nonsense!" exclaimed the colonel. "I stationed an operative there to prevent that very thing. No doubt it is a mistake. However, I'll do what I can."

He excused himself and hurried off. Then the man in black turned to Neville and said in an icy voice, "And you, sir—what is it you wish?"

Neville's mind worked instantly. He did not want to express interest in Mr. Carstairs, nor did he care to reveal to the showman his acquaintance with the colonel. So he said quickly:

"The curtain ... I was curious as to how it worked ... you see, once I...."

"Joe," called the man, wheeling, "explain the curtain to the gentleman."

Joe came. He led the way to the switchboard and began a spiel about its intricacies. Neville looked on, understanding it only in the high spots, for the board was a jumble of gadgets and doodads, and it was not long before he began to suspect that the long-winded explanation was a unique variety of double-talk.

"See?" finished the man, "it's as simple as that. Clever, eh?"

"Yes, indeed. Thanks."

Neville started back to the stage, but the announcer barred his way.

"The exit is right behind you, sir," he said in a chilly voice. The words and intonation were polite, but the voice had that iron-hand-in-velvet-glove quality used by tough bouncers in night clubs when handling obstreperous members of the idle rich. They were accompanied as well by a glance so uncanny and so charged with malignancy that Neville was hard put to keep on looking him in the eye and murmur another "Thank you."

But before Neville reached the exit, Colonel Frawley came through.

"Oh, hello. Where is Carstairs?"

Neville shook his head.

"A moment ago he was talking with his impersonator," offered the announcer, seeming to lose all interest in Neville's departure. "I'll see if he is still here. He may have gone into the actor's dressing room."

But as he spoke a dressing room door opened and Carstairs came out of it, smiling contentedly. He turned and called back to the actor inside:

"Thanks again for an enjoyable evening. You bet I'll see you next year." Then he came straight over to Frawley and hooked his arm in his. "All right, Colonel, shall we go? And Mr. Allington, too?"

Neville nodded, luckily recognizing his latest assumed name. Out of the corner of his eye he saw the dressing-room door slammed shut by the actor inside of it.

"I hate to hurry you, gentlemen," said the announcer, "but we blast out at once."

The trio retrieved their helmets and strode off into the night. By then, the skyport was deserted and the floodlights taken in. When they reached the copter they saw the flash and heard the woosh as the big ship roared away on her rockets.

"Back to the old routine and bedroom," sighed Mr. Carstairs as he heard it leave. "It was good while it lasted, though."

"Yep," chuckled the colonel. "Hop in and we'll drop you at home."

Three minutes later they were before the Carstairs' truly-palatial mansion.

"Come in a second and speak to Mariquita," invited the magnate.

"No, thanks. It's late...."

Neville's elbow dug into his superior's ribs with a vicious nudge.

"... but if you insist...."

Mrs. Carstairs met them in the ante-room, greeted the inspector cordially and kissed her husband affectionately. They stood for the rest of the brief visit with their arms circled about one another. Her Spanish blood heritage was evident in her warm dark eyes and proud carriage. Equally evident, were the lines of past suffering in her face. It did not take a detective to see that here was a pair who had at last found mutual consolation.

On the way back to headquarters nothing was said. But later, while they were undressing, the colonel remarked:

"Good show. Did it throw your mind off your troubles?"

"No," said Neville curtly.

"Well," said the inspector, "a good night's sleep will. G'night."

There was no sleep that night for Billy Neville, though. He spent it mentally digesting all the stuff he had read that afternoon, and all that he had seen and heard that night. He devoted many weary hours to a review of his own mind's copy of the famous rogue's gallery at the Luna Central Base. The picture he wanted wasn't there. He wished fervently he had taken that refresher course on hypnotism when they had offered it to him two years ago. He wished he had not been such a softy as to let himself be shunted off to look at that dizzy switchboard. He should have taken a closer look at the showboat people. He wished ... but hell, what was the use? Pallas' half-sized sun was up and today was another day.

The meanest of all trails to follow is a cold trail. Or almost. Perhaps the worst is no trail. It is hard to keep interest up. Then, too, Pallas was a dull place—orderly as a church, where people simply worked and behaved themselves. The days dragged by, and nothing out of the way happened. Neville went through the motions of trying to sell clothing in majestic lots of hundreds, but no one was interested. He even talked vaguely of looking for a site for an outer warehouse for his company. He saw Mr. Carstairs often and became a welcome guest at the house.

Yet with this lack of incident, Neville was at all times alert in his study of the man he was watching. He could not help remembering that little while after the showboat performance that Carstairs had been absent from them. He particularly kept his mind open for any slow change in him, such as could be the result of a mysterious delayed-action drug or from post-hypnotic effect. But there was none that he could detect, nor did the colonel notice anything of the sort, though Neville spoke to him on the subject several times.

The first indication that all was not well came from Mariquita Carstairs herself. Neville happened in one day for lunch and found her red-eyed and weeping. Then she added that she had worried a great deal the last few days about her husband's health.

"When I watch him when he doesn't know it," she said anxiously, "he looks different —so wily, crafty and wicked. And he is not like that. He is the dearest man in the world. He must be sick."

Neville left as early as possible, and at once consulted Frawley.

"Yes," said the inspector thoughtfully, "she's right. In the last day or so I've noticed a subtle change myself. I blundered into his office the other day and he had his safe open and mountains of files all over the floor. He was actually rude to me. Wanted to know what I meant by barging in on him like that. Imagine!"

The communicator on the wall buzzed. The signal light showed it was the skyport calling. Neville could overhear what the rasping voice was saying.

"Peters at airport reporting. Mr. Carstairs has made reservation on ship Fanfare for passage to Vesta. Ship arrives in half an hour; departs immediately."

By the time Frawley had acknowledged and cut the connection, Neville had already ordered the copter.

"I'm on my way," he cried. "This is it ! Give me a complete travel-kit quick and an Extra-Special transformation outfit."

Two minutes later Neville was on his way to the landing field, the two valuable bags between his knees. He was there when the spaceship landed, and was inside it before Simeon Carstairs showed up. The copter soared away the moment he had left it. Carstairs would not know he had a shadow.

Neville went straight to the captain, whom he found resting momentarily in his cabin. He flashed his badge.

"I am your steward from here to Vesta," he told him. "Send for your regular one at once and give him his instructions."

"But my dear sir," objected the captain, rising from his bunk, "as much as I would like to cooperate, I cannot do that. You must know that under the new regulations all members of a ship's crew must be photographed and the pictures posted in prominent parts of the ship. It is your own police rule and is for the protection of passengers from imposters."

"Never mind that," snapped Neville, "get him in here."

The steward came and Neville studied him carefully. He was a swarthy man with heavy shoulders and thick features. His eyes were jet black. But his height was little different from that of the special investigator.

"Say something," directed Neville, "I want to hear your voice. Recite the twelve primary duties of a steward."

The man obeyed.

"It's okay," announced Neville when he had finished. "I can do it."

He gave the captain a word of warning, then went with the steward to his room. There he handed the astonished man a hundred-sol credit note and told him to hit the bunk.

"Here's your chance to catch up on your rest and reading," said Neville grimly. "You don't leave that bunk until I tell you to, y'understand? If you do, it will cost you five years in the mines of Oberon."

The steward gasped and lay back on the pillow. He gasped some more when Neville yanked his box of transformations open and spread its contents on the table. His eyes fairly bulged as he watched Neville shoot injections of wax into his deltoids and biceps until the policeman's shoulders were the twins of his own. He saw him puff up his face, thicken the nose and load the jowls, and after that paint himself with dye, not omitting the hair. Then, marvel of marvels, he saw him drop something in his eyes and sit shuddering for a few seconds while the stuff worked. When the eyes were opened again they were as black as his own!

"How's dis, faller?" asked Neville in the same flat, sullen tone the steward had used in the cabin. "Lanch is sarved, sor ... zhip gang land in one hour, marm ... hokay?"

"Gard!" was the steward's last gasp. Then he lapsed into complete speechlessness.

Neville darted out into the passage. The baggage of the sole passenger to get on at Pallas lay in the gangway, and its owner, Mr. Carstairs, stood impatiently beside it. He growled something about the rotten service on the Callisto-Earth run, but let the steward pick up the bags. Then he followed close behind.

"Lay out your t'ings, sor?" queried Neville, once inside the room.

"No," said Carstairs savagely. "When I want anything I will ask for it. Otherwise, stay out of my room."

"Yas, sor," was what Neville said in return, but to himself "Phew! The old boy has changed. I don't know where I'm going, but I'm on my way."

He had no intention of obeying Carstairs' injunction to stay out of his room. That night he served the evening meal, and with it was a glass of water. He had taken the precaution to drop a single minim of somnolene in it—that efficacious sleep-producer permitted to only seven members of the I.P., tasteless, colorless and odorless, and without after-effect.

In the second hour of the sleep period, the false steward stole down the passage and with a pass key unfastened the door lock. There was an inside bolt to deal with as well, but an ingenious tool that came with the travel-kit took care of that. A moment later Neville was in the slumbering man's room. Five minutes later he was back in his own, and stacked on the deck beside him was all the baggage the magnate of Pallas had brought with him.

One piece opened readily enough, and its contents seemed innocuous. But the methodical police officer was not content with superficial appearances. He examined the articles of clothing in it, and the more he looked the more his amazement grew. There were no less than four sets of costumes in it. Moreover, they were for men of different build. One stout, two medium, one spare. In the bottom was a set of gray canvas bags—slip-covers with handles. Neville puzzled over them a moment, then recognized their function. They were covers for the very baggage he was examining. He had to use special tools to open the second bag and found it contained a makeup kit quite the equal of his own.

"Ouch," he muttered. "This guy is as good as I am."

The third and heaviest bag was a tougher job. It was double-locked and strapped, and heavy seals had been put on the straps. The Extra-Special travel-kit equipment took care of the locks and seals, but the contents of the bag were beyond anything a travel-kit could handle. They were documents—damning documents—neatly bundled up, each bound with its own ribbon and seal. Had Neville had twenty-four hours in a well-equipped laboratory with a sufficient number of assistants, he might have forged passable but less incriminating substitutes for them. As it was, he was helpless to do a very artistic job of switching. One package dealt with certain long-forgotten passages in Mrs. Carstairs' life, while others dealt with certain business transactions.

From that case, Neville chose to abstract all of them except the one which formed the outer wrapper. To make up the bulk he filled the bundle with blank paper, tied it up again and resealed it. He dealt likewise with the packet that contained the formulae for the radiation extraction process. And, for the good of the Service, he pursued the same course with regard to a rather detailed report on the foibles and weaknesses of a certain police colonel stationed in Pallas. There was not a hint of scandal or corruption in that, but often ridicule is as potent a weapon as vilification. After that came the tedious business of censoring the rest, repacking the bag as it had been, and restoring the locks and seals. The gently snoring Carstairs never knew when his bags were returned to him, nor heard the faint scuffling as his door was rebolted and relocked.

"Vasta, sor, in one hour," announced his steward to him eight hours later. "Bags out, sor?"

"When we get there," growled the magnate, yawning heavily, glancing suspiciously about the room. He locked the door behind the steward, didn't leave until the ship was cradled.

Neville watched him go ashore. Then he hurried in to see the skipper again.

"You will be compensated for this," he said hurriedly. "You can have your steward back on the job again. How long do you stay here?"

"Three hours, curse the luck. We usually touch and go, but this time I have an ethergram ordering me to wait here for a special passenger. Why in hell can't these hicks in the gravel belt learn to catch a ship on time?"

"Ah," breathed Neville. "That makes a difference. I think I'll stay with you. Have you a vacant room where I can hang out for the remainder of the voyage?"

"Yes."

Neville did another lightning change—back to Special Investigator Billy Neville of the I.P.—uniform and all. He was standing near the spacelock when the expected passenger came aboard.

Neville could not suppress a murmur of approval as he saw his quarry approaching. As an artist in his own right, he appreciated artistry when he saw it. The man coming down the field was Carstairs, but what a different Carstairs! He was more slender, he had altogether different clothes on, he had a different gait. His complexion was not the same. But the height was the same, and the bags he carried were the same shape and size, except for their gray canvas coverings. There was a little notch in the right ear that he had not troubled to rectify in the brief time he had had for his transformation in what was undoubtedly his pre-arranged hideaway on Vesta.

"What is the next stop, skipper?" Neville whispered to the captain.

"New York."

"I'll stay out of sight until then."

Any passenger on that voyage of the Fanfare will tell you that her captain should have been retired years before. He made three bad tries before he succeeded in lowering his ship into the dock at the skyport. The passengers did not know, of course, that he had to stall to permit a certain member of the I.P. to make a parachute landing from the stratosphere.

Billy Neville hit the ground not four miles from the designated skyport. A commandeered copter took him to it just in time to see the squat passenger vessel jetting down into her berth. He looked anxiously about the station. There was not a uniformed man in sight except a couple of traffic men of the local detachment. He needed help and lots of it.

Neville had no choice but to play his trump card. It was a thing reserved only for grave emergencies. But he considered the present one grave. He took his police whistle out of his vest pocket and shrilled it three times. It was a supersonic whistle—its tone only audible to first-class detectives having tuned vibrators strapped over their hearts. To sound a triple supersonic call was the police equivalent of sending out an eighth alarm fire-call. But Neville blew the blast. Then waited.

A man strolled up and asked the way to Newark.

"Wait," said Neville, only he did not use words but merely lifted his right eye-brow slightly. It was not long before four others came up and craved directions as to how to get to Newark. He lit a cigarette as they gathered around.

"The ship Fanfare has just landed—out of Callisto with wayside stops in the Belt. There is a passenger carrying three bags covered by gray canvas. Tail him. Tail everybody he contacts. If you need help, ask local HQ. If they can't give enough, ask Luna. But whatever you do, don't make a pinch. This guy is small fry. My code number is...."

Neville knew better than to flash a badge on these men, even if he was in uniform. Both badges and uniforms could be counterfeited. But he knew that they knew from his procedure that he was a department agent.

"There he comes," he warned, and promptly ducked behind a fruit stall and walked away.

Headquarters readily gave him a rocket and a driver to take him to Lunar Base. He had no trouble breaking down the barriers between him and the second most important man in the I.P.—the first being the General-General in Charge of Operations. The man he wanted to see was the Colonel-General, Head of the Bureau of Identification.

Neville allowed himself to be ushered into the office, but it was not without trepidation, for old Col.-General O'Hara had a vile reputation as a junior-baiter. He was not at all reassured when he heard the door click to behind him with the click which meant to his trained ears that the door would never be opened again without the pressure of a foot on a certain secret pedal concealed somewhere in the room. Nor did the appearance of the man behind the desk do anything to relieve his own lack of ease.

O'Hara was a gnome, scarcely five feet tall, with bulging eyes and wild hair that stood helter-skelter above his wrinkled face. He was staring at his desk blotter with a venomous expression, and his lower lip hung out a full half-inch. Neville stood rigidly at attention before him for a full three minutes before the old man spoke. Then he looked up and barked a caustic, "Well?"

"I am Special Investigator Neville, sir," he said, "and I want the pedigree of a certain notorious criminal whose picture is lacking in the gallery."

"Stuff and nonsense!" snorted the Colonel-General. "There is no such criminal. Man and boy, I have run this bureau since they moved it to the Moon. Why—oh, why—do they let you rookies in here to bother me?"

"Sir," said Neville stiffly, "I am no rookie. I am a...."

"Bah! We have—or had, at last night's report—eight hundred and ninety-three of your 'specials' half of them on probation. When you've spent, as I have spent, sixty-two years...."

"I'm sorry, sir," urged Neville, "we can't go into that now. Do what you want to with me afterwards, but I assure you this is urgent. I am on the trail of a higher-up in the Callisto-Trojan extortion racket. Do I get the information I am after, or do I turn in my agent badge?"

"Huh?" said the old general, sitting up and looking him straight in the face. "What's that?"

"I mean it, sir. I have trailed one of the higher-up stooges to Earth and set shadows on him. I think I have seen the king-pin of the mob, and I want to know who he is," Neville went on to describe the presentation of the showboat entertainment, with special emphasis on his hunches and suspicions. To the civilian mind, the things he told might seem silly, but to a policeman they were fraught with meaning. His description of the suspect was not one of appearance; it was a psychological description—a description based wholly on intuition and not at all on tangibles. He had not proceeded far before the wrinkled old man thumped the desk with a gnarled fist.

"Hold it," he said, "I think I know the man you mean. But give me time—my memory is not what it used to be."

Neville waited patiently at the rigid attitude of attention while the shriveled old veteran before him rocked back and forth in his chair with the lids closed over his bulging eyes, cracking his bony knuckles like castanets. O'Hara seemed to have gone into something like a trance. Suddenly, after a quiver of the eyelids, he stared up at Neville.

"It all comes back now. You were a member of the class of '14 and I was instructor—a major then. I took all of you to see a certain show on Broadway, as they call it, in order...."

"Yes, sir," cried Neville, eagerly, "that was it! You told us the principal character in the play was the most dangerous potential criminal of our generation and that we should mark him well and remember. It was a very hard assignment, for we only saw him from before the foot-lights and he was acting the part of a Viking chieftain and most of his face was covered with false white whiskers."

Old O'Hara smiled.

"You seem to have been an apt pupil. At any rate, that man was Milo Lunko, a thoroughly unprincipled and remarkably clever blackmailer. He was so clever, in fact, that we were never able to make an arrest stick, let alone bring him to trial. That accounts for the absence of his picture from the gallery. He was also clever enough to fake his own death. The evidence we have as to that was so convincing we closed the file on him."

"It's open again," said Neville grimly. "How did he work?"

"Lunko was not only an actor, but a producer and clever playwright as well. He might have achieved fame and fortune legitimately, but he became greedy. He teamed up with a shady character named Krascbik who ran a private investigating agency, specializing in social scandals. Krascbik's men would study the private life of influential individuals and dig out their scandals. They would provide Lunko with slow-motion camera studies of them so he could learn the peculiarities of their carriage, mannerisms, voice, and all their other idiosyncracies.

"Lunko's next step would be to write a scurrilous play based on the confidential information provided by Krascbik, and put it in rehearsal, using characters that resemble the actual principals...."

"But that's libel," objected Neville, "why couldn't you haul him in?"

"Blackmail, young man, is a delicate matter to handle. The injured party shrinks from publicity and usually prefers to pay rather than have his scandal aired. Lunko never actually publicly produced any of those nauseous plays. His trick was to invite the victim to a preview—a dress rehearsal, then let Nature take its course. Invariably, the victim was frightened and tried to induce him to call off the presentation. Lunko would protest that the play had been written in good faith and had already cost him a great deal of money. The pay-off, of course, was always big. Lunko drove many people to the brink of ruin.

"One man did refuse to play with him, and turned the case over to us. Lunko carried out his threat and produced the show, much to the delight of the scandal-mongers. It was outrageously libelous and we promptly closed the joint and took him in...."

"And then...."

"And then," croaked O'Hara, rolling his pop-eyes toward the ceiling and pursing his lips, "and then we let him go. He had a trunkful of data on many, many important people. Some of them, I hate to tell you, were my seniors in this very Service. We could do nothing about it, for, unfortunately, all the stuff he had on them was true. We might have sent him to the mines for a short term, but he would have retaliated by standing our entire civilization on its head with his exposures. We compromised by letting him escape and go into exile. The understanding was that he was never to come inside the orbit of Mars. A while after that, he was reported killed in a landslide on Europa. We shut the book and proceeded to forget him."

"He mimicked the character exactly?"

"Not exactly. Just enough to clearly indicate them. Although, I am convinced that, if he chose, he could have taken off any person he had studied, with enough fidelity to fool anybody except perhaps a man's own wife."

Neville gave a little start. That was the item that had slowed him the most. Had Lunko improved his technique to the extent that he could even fool a wife? Was the Carstairs he was trailing really Carstairs, or an understudy? He had deceived both his old friend and his own wife for a time, but even they had admitted noting a subtle change. Who was this phoney Carstairs? Where was the real Carstairs? Or, Neville wondered, was his original theory of drugs or hypnotism correct?

"Thank you, General," he said. "You have been a big help. I have to go over to Operations now and get the past and future itineraries of the showboat. In another hour, I may begin to know something about this case."

"It's nothing," said O'Hara, promptly closing his eyes and folding his knotty fingers on his breast. "It's all in the day's work. Luck to you."

Neville heard the click as the secret door lock was released and he knew the interview was terminated. He backed away, stepped through the door and out into the corridor.

Neville went straight to the great library where the I.P. records are kept. An attendant brought him the bulky folder on the old Lunko gang. Neville found it engrossing reading, and the day waned and night came before he had committed all its contents to memory.

Billy Neville obtained a televise connection with Tellurian headquarters.

"How are your shadows doing?"

He had already learned the real identity of the man he had trailed from Pallas; he was an actor belonging to the original ring and went by the name of Hallam.

"Our shadows are doing fine," replied the officer at the other end, "but your friend Hallam seems unhappy. He made two calls on a high officer of the Radiation Corporation and after the second one he came very angry and ruffled looking. He has also called on several other persons, known to us as extortioners, and at least two of those are on his trail with blood in their eye."

"I know," chuckled Neville. "He sold 'em a bill of goods—rolls of blank paper. They think they've been double-crossed. And they have, only I'm the guy that did it. But say, we can't have him killed—not yet. Better round up all his contacts and put 'em away, incommunicado. I'm hopping a rocket right now and will be with you in a jiffy."

It did not take the police long to make the little jump from Luna to Tellus, and a couple of hours later Neville was confronting Hallam in a special cell. In his hands he held a first-class ticket to Titan in the Saturn group, which had come out of Hallam's pocket, as well as a handbill of the showboat announcing an appearance there in the near future.

"I just wanted to study your current rig, Hallam," explained Neville, opening up his makeup kit. "Impersonation is a game that more than one can play at. I'm going in your place to Titan. I'm a teeny-weeny bit curious as to what happens to your victims. Extortion carries good stiff sentences, but they lack the finality of that for murder."

The Neville that left the cell was the exact duplicate of Hallam, and by dint of exacting search of the actor's trick garments and the use of adroit questioning under pressure, the Special Investigator knew exactly what he had to do. And he knew ever better, after the spaceship he was riding settled down into the receiving berth on Titan. An actor of Lunko's—a skinny, gaunt fellow—was on hand to meet him, and a little later they conferred in a well-screened spot with three of Lunko's jackals.

"The layout here is a cinch," explained the skinny actor. "The two biggest shots are the president of the Inter-satellite Transportation Company and the fellow who owns the bulk of shares in the phlagis plantations. A year or so ago they were mixed up in a most ludicrous near-scandal that people are still tittering over. A situation like that is a natural for us. Lunko has already sent the script on ahead. It's funny enough to tickle the town, but not so raw it will make the principals sore. We will deal with them in the usual way, when they come backstage after the show."

"Uh, huh," said Neville, and asked to see the descriptions. They lit up the projector and began running three-dimensional views of their intended victims. The preliminary studies had been most comprehensive and Neville knew before the hour was up that not a mannerism or intonation of voice had been overlooked. To persons skilled in disguise the problem was not so much one of imitation, but of introducing a telling imperfection that would allay suspicion of a possible more perfect imitation later.

The remainder of their time until the showboat came, they spent in gruelling rehearsals.

Neville watched the show from the wings and was gratified to note the considerable sprinkling of plainclothes-men in the audience. The show was good, as it had been before, and the audience was highly enthusiastic. Then came the curtain call and the announcement of the special performance. When the lights were down and his cue came, Neville walked on and performed his silly role. Then there was a hubbub of applause and wild calls for an encore. A few minutes later the two men they had lampooned came backstage, grinning sheepishly, yet apparently resolved to show themselves good sports.

"You would have more privacy in the dressing rooms," suggested Lunko suavely, and ushered each into the private closet of the man who had just mimicked him. Neville found himself face to face with a near-double.

"Step on it," said Lunko harshly, who had followed. He flicked on a peculiarly brilliant overhead light, and the startled victim looked up at it with the helpless, hopeless gaze of a lamb being led to the slaughter. "Change your makeup while I drag the dope out of him. I've got another one to do after this, you know."

Neville grunted and began plucking away the comedy elements of his burlesque get-up. Then, with the deftness of long experience he made his appearance match the poor dupe's to the chair. Meanwhile Lunko had forced his victim into the depths of hypnotic trance and was extracting all the secret knowledge that the snooping jackals had been unable to obtain indirectly.

"You've got it all, now?" asked Lunko, impatiently, "The combination of his safe, his office and home habits? I've drained him dry, I believe."

Neville nodded.

"Stand back, you fool!" screamed Lunko, as Neville awkwardly stepped against him just as he was about to swing the bludgeon that would finish the now valueless victim, "we've just time to get this one into the incinerator...."

He never finished, for at that instant Neville sprang from the balls of his feet and a heavy fist smashed into the blackmailer's jaw with a crash that told of a shattered jawbone. Another battering ram of a fist smashed him to the floor.

Neville's high-frequency whistle was out and the shrill, inaudible alarm tingling on the breasts of the key men waiting outside. Then he was dashing for the adjoining dressing room where a similar little drama was just being brought to its close. A swift jab of fire from the blaster that appeared magically in Neville's hand sent the actor to his death. Other policemen were dashing up and the second hypnotist suddenly lost interest in his surroundings, going down onto his knees, a mass of battered pulp.

Then Neville sat down and began thoughtfully removing the makeup he so detested.

"I wonder," he complained to himself, "whether I'm ever going to get that leave."