"Drink some more of this," the voice said, and cold water splashed on Jason\'s face and some of it trickled down his throat making him cough. Something hard was pressing into his back and his wrists hurt. Memory seeped back slowly, the fight, the capture and the potion that had been forced upon him. When he opened his eyes he saw a flickering yellow lamp overhead, hung from a chain. He blinked at it and tried to gather enough energy to sit up. A familiar face swam in front of the light and Jason squinted his eyes at it and groaned.

"Is that you Mikah—or are you just part of a nightmare?"

"There is no escape from justice, Jason. It is I, and I have some grave questions to put to you."

Jason groaned again. "You\'re real all right. Even in a nightmare I wouldn\'t dare dream up any lines like that. But before the questions, how about telling me a thing or two about the local setup, you should know something since you have been a slave of the D\'zertanoj longer than I have." Jason realized that the pain in his wrists came from heavy iron shackles. A chain passed through them and was stapled to a thick wooden bar on which his head had been resting. "Why the chains—and what is the local hospitality like?"

Mikah resisted the invitation to impart any vital information and returned irresistibly to his own topic.

"When I saw you last you were a slave of Ch\'aka, and tonight you were brought in with the other slaves of Ch\'aka and chained to the bar while you were unconscious. There was an empty place next to mine and I told them I would tend you if they placed you there, and they did. Now there is something I must know. Before they stripped you I saw that you were wearing the armor and helmet of Ch\'aka. Where is the man—what happened to him?"

"Me Ch\'aka," Jason rasped, and burst out coughing from the dryness in his throat. He took a long drink of water from the bowl. "You sound very vindictive, Mikah you old fraud. Where is all the turn-the-other-cheek stuff now? Don\'t tell me you could possibly hate the man just because he hit you on the head, fractured your skull and sold you down the river as a slave reject? In case you have been brooding over this injustice you can now be cheered because the evil Ch\'aka is no more. He is buried in the trackless wastes and after all the applicants were sifted out I got the job."

"You killed him?"

"In a word—yes. And don\'t think that it was easy since he had all the advantages and I possessed only my native ingenuity, which luckily proved to be enough. It was touch and go for a while because when I tried to assassinate him in his sleep—"

"You what?" Mikah Samon hissed.

"Got to him at night. You don\'t think anyone in his right mind would tackle a monster like that face-to-face do you? Though it ended up that way, since he had some neat gadgets for keeping track of people in the dark. Briefly, we fought, I won, I became Ch\'aka, though my reign was neither long nor noble. I followed you as far as the desert where I was neatly trapped by a shrewd old bird name of Edipon who demoted me back to the ranks and took away all my slaves as well. Now that\'s my story. So tell me yours, where we are, what goes on here?"

"Assassin! Slave holder!" Mikah reared back, as far as he could under the restraint of the chain, and pointed the finger of judgment at Jason. "Two more charges must be added to your role of infamy. I sicken myself, Jason, that I could ever have felt sympathy for you and tried to help you. I will still help you, but only to stay alive so that you may be taken back to Cassylia for trial and execution."

"I like that example of fair and impartial justice—trial and execution." Jason coughed again and drained the bowl of water. "Didn\'t you ever hear of presumed innocence until proven guilty? It only happens to be the mainstay of all jurisprudence. And how could you possibly justify trying me on Cassylia for actions that occurred on this planet—that aren\'t crimes here? That\'s like taking a cannibal away from his tribe and executing him for anthropophagy."

"What would be wrong with that? The eating of human flesh is a crime so loathsome I shudder to think of it. Of course a man who does that must be executed."

"If he slips in the back door and eats one of your relatives, you certainly have grounds for action. But not if he joins the rest of his jolly tribe for a good roast of enemy. Don\'t you see the obvious point here—that human conduct can only be judged in relation to its environment? Conduct is relative. The cannibal in his society is just as moral as the churchgoer in yours."

"Blasphemer! A crime is a crime! There are moral laws that stand above all human society."

"Oh no there are not, that\'s just the point where your medieval morality breaks down. All laws and ideas are historical and relative, not absolute. They are relevant to their particular time and place and taken out of context they lose their importance. Within the context of this grubby society I acted in a most straightforward and honest manner. I attempted to assassinate my master—which is the only way an ambitious boy can get ahead in this hard world, and which was undoubtedly the way Ch\'aka himself got the job in the first place. Assassination didn\'t work but combat did, and the results were the same. Once in power I took good care of my slaves, though of course they didn\'t appreciate it since they didn\'t want good care, they only wanted my job, that being the law of the land. The only thing I really did wrong was to not live up to my obligations as a slave holder and keep them marching up and down the beaches forever. Instead I came looking for you and was trapped and broken back to slavery where I belong for pulling such a stupid trick."

The door crashed open and harsh sunlight streamed into the windowless building. "On your feet slaves!" a D\'zertano shouted in through the opening.

A chorus of shufflings and groans broke out as the men stirred to life. Jason could see now that he was one of twenty slaves shackled to the long bar, apparently the entire trunk of a good-sized tree. The man chained at the far end seemed to be a leader of sorts because he cursed and goaded the others to life. When they were all standing he snapped his commands in a hectoring tone of voice.

"Come on, come on, first come best food. And don\'t forget your bowls, put them away so they can\'t drop out, remember nothing to eat or drink all day unless you have a bowl. And let\'s work together today, everyone pull his weight, that\'s the only way to do it. That goes for all you men, specially you new men. Give them a day\'s work here and they give you a day\'s food...."

"Oh shut up!" someone shouted.

"... And you can\'t complain about that," the strawboss whined on, unperturbed. "Now altogether ... one ... bend down and get your hands around the bar, get a good grip and ... two ... lift it clear of the ground, that\'s the way. And ... three ... stand up and out the door we go."

They shuffled out into the sunlight and the cold wind of dawn bit through his Pyrran coverall and the remnants of Ch\'aka\'s leather trappings that Jason had been allowed to keep. His captors had torn off the claw-studded feet but not bothered the wrappings underneath, so they hadn\'t found his boots. This was the only bright spot on an otherwise unlimited vista of blackest gloom. Jason tried to be thankful for small blessings, but only shivered some more. As soon as possible this situation had to be changed since he had already served his term as slave on this backwoods planet and was cut out for better things.

On order the slaves lined up against the walls of the yard. Presenting their bowls like scruffy penitents they accepted dippers of lukewarm soup from another slave who pushed along a wheeled tub of the stuff: he was chained to the tub. Jason\'s appetite vanished when he tasted the sludge. It was krenoj soup, and the desert tubers tasted even worse—he hadn\'t thought it was possible—when served up in a broth. But survival was more important than fastidiousness, so he gulped the evil stuff down.

Breakfast over they marched out the gate into another compound and fascinated interest displaced all of Jason\'s concerns. In the center of the yard was a large capstan into which the first group of slaves were already fitting the end of their bar. Jason\'s group, and the two others, shuffled into position and seated their bars, making a four spoked wheel out of the capstan. An overseer shouted and the slaves groaned and threw their weight against the bars until they shuddered and began to turn, then trudging slowly they kept the wheel moving. Once this slogging labor was under way Jason turned his attention to the crude mechanism that they were powering.

A vertical shaft from the capstan turned a creaking wooden wheel that set a series of leather belts into motion. Some of them vanished through openings into a large stone building, while the strongest strap of all turned the rocker arm of what could only be a counterbalanced pump. This all seemed like a highly inefficient way to go about pumping water since there certainly must be natural springs and lakes somewhere around. The pungent smell that filled the yard was hauntingly familiar, and Jason had just reached the conclusion that water couldn\'t be the object of their labors when a throaty gurgling came from the standpipe of the pump and a thick black stream bubbled out.

"Petroleum—of course!" Jason enthused out loud, then bent his attentions to pushing when the overseer gave him an ugly look and cracked his whip menacingly.

This was the secret of the D\'zertanoj, and the source of their power. Mountains were visible nearby, and hills, towering above the surrounding walls. The captured slaves had been drugged so they would not even know in which direction they had been brought to this hidden site, or how long the trip was. Here in this guarded valley they labored to pump the crude oil that their masters used to power their big desert wagons. Or did they use crude oil for this? The petroleum was gurgling out in a solid stream now, and running down an open trough that vanished through the wall into the same building as the turning belts. And what barbaric devilishness went on in there? A thick chimney crowned the building and produced clouds of black smoke, while from the various openings in the wall came a tremendous stench that threatened to lift the top off his head.

At the same moment that he realized what was going on in the building a guarded door was opened and Edipon came out, blowing his sizable nose in a scrap of rag. The creaking wheel turned and when its rotation brought Jason around again he called out to him.

"Hey, Edipon, come over here. I want to talk to you. I\'m the former Ch\'aka, in case you don\'t recognize me out of uniform."

Edipon gave him one look, then turned away dabbing at his nose. It was obvious that slaves held no interest for him, no matter what their position had been before their fall. The slave-driver ran over with a roar, raising his whip, while the slow rotation of the wheel carried Jason away. He shouted back over his shoulder.

"Listen to me—I know a lot and can help you." Only a turned back for an answer and the whip was already whistling down. It was time for the hard sell. "You had better hear me—because I know that what comes out first is best. Yeow!" This last was involuntary as the whip landed.

Jason\'s words were without meaning to the slaves as well as the overseer who was raising his whip for another blow, but their impact on Edipon was as dramatic as if he had stepped on a hot coal. He shuddered to a halt and wheeled about, and even at this distance Jason could see that a sickly gray tone had replaced his normal browned color of his skin.

"Stop the wheel!" he shouted.

This unexpected command drew the startled attention of everyone. The gape-mouthed overseer lowered his whip while the slaves stumbled and halted and the wheel groaned to a stop. In the sudden silence Edipon\'s steps echoed loudly as he ran to Jason, halting a hand\'s breadth away, his lips drawn back from his teeth with tension as if he were prepared to bite.

"What was that you said?" He hurled the words at Jason while his fingers half-plucked a knife from his belt.

Jason smiled, looking and acting calmer than he felt. His barb had gone home, but unless he proceeded carefully so would Edipon\'s knife—into his stomach. This was obviously a very sensitive topic.

"You heard what I said—and I don\'t think you want me to repeat it in front of all these strangers. I know what happens here because I come from a place far away where we do this kind of thing all the time. I can help you. I can show you how to get more of the best, and how to make your caroj work better. Just try me. Only unchain me from this bar first and let\'s get to some place private where we can have a nice chat."

Edipon\'s thoughts were obvious. He chewed his lip and looked hotly at Jason, fingering the edge of his knife. Jason only returned a smile of pure innocence and tapped his fingers happily on the bar, just marking time while he waited to be released. Yet in spite of the cold there was a rivulet of sweat trickling down his spine. He was gambling everything on Edipon\'s intelligence, that the man\'s curiosity would overcome the immediate desire to silence the slave who knew so much about things so secret, hoping that he would remember that slaves could always be killed, and that it wouldn\'t hurt to ask a few questions first. Curiosity won and the knife dropped back into the sheath while Jason let his breath out in a relieved sigh. It had been entirely too close, even for a professional gambler; his own life on the board was a little higher stakes than he enjoyed playing for.

"Release him from the bar and bring him to me," Edipon ordered, then strode agitatedly away. The other slaves watched wide-eyed as the blacksmith was rushed out, and with much confusion and shouted orders Jason\'s chain was cut from the bar where it joined the heavy staple.

"What are you doing?" Mikah asked, and one of the guards backhanded him to the ground. Jason just smiled and touched his finger to his lips as his chain was released and they led him away. He was free from bondage and he would stay that way if he could convince Edipon that he would be better off in some capacity other than dumb labor.

The room they led him to contained the first touches of decoration or self-indulgence that he had seen on this planet. The furniture was carefully constructed, with an occasional bit of carving to brighten it, and there was a woven cover on the bed. Edipon stood by a table, tapping his fingers nervously on the dark polished surface. "Lock him up," he ordered the guards, and Jason was secured to a sturdy ringbolt that projected from the wall. As soon as the guards were gone he stood before Jason and drew his knife. "Tell me what you know or I will kill you at once."

"My past is an open book to you, Edipon. I come from a land where we know all the secrets of nature—"

"What is the name of this land? Are you a spy from Appsala?"

"I couldn\'t very well be one since I have never heard of the place." Jason pulled at his lower lip, wondering just how intelligent Edipon was, and just how frank he could be with him. This was no time to get tangled up in lies about planetary geography: it might be best to try him on a small dose of the truth. "If I told you I came from another planet, another world in the sky up among the stars, would you believe me?"

"Perhaps. There are many old legends that our forefathers came from a world beyond the sky, but I have always dismissed this as religious drivel, fit only for women."

"In this case the girls happen to be right. Your planet was settled by men whose ships crossed the emptiness of space as your caroj pass over the desert. Your people have forgotten about that and lost the science and knowledge you once had, but in other worlds the knowledge is still held."

"Madness!"

"Not at all, it is science, though many times confused as being the same thing. I\'ll prove my point. You know that I could never have been inside your mysterious building out there, and I imagine you can be sure no one has told me its secrets. Yet I\'ll bet you that I can describe fairly accurately what is in there—not from seeing the machinery, but from knowing what must be done to oil in order to get the products you need. Do you want to hear?"

"Proceed," Edipon said, sitting on a corner of the table and balancing the knife loosely in his palm.

"I don\'t know what you call it, the device, but in the trade it is a pot still used for fractional distillation. Your crude oil runs into a tank of some kind, and you pipe it from there to a retort, some big vessel that you can seal airtight. Once it is closed you light a fire under the thing and try to get all the oil to an even temperature. A gas rises from the oil and you take it off through a pipe and run it through a condenser, probably more pipe with water running over it. Then you put a bucket under the open end of the pipe and out of it drips the juice that you burn in your caroj to make them move."

Edipon\'s eyes opened wider and wider while Jason talked until they stuck out of his head like boiled eggs. "Demon!" he screeched and tottered towards Jason with the knife extended. "You couldn\'t have seen, not through stone walls, yet only my family have seen, no others—I\'ll swear to that!"

"Keep cool, Edipon, I told you that we have been doing this stuff for years in my country." He balanced on one foot, ready for a kick at the knife in case the old man\'s nerves did not settle down. "I\'m not out to steal your secrets, in fact they are pretty small potatoes where I come from since every farmer has a still for cooking up his own mash and saving on taxes. I\'ll bet I can even put in some improvements for you, sight unseen. How do you monitor the temperature on your cooking brew? Do you have thermometers?"

"What are thermometers?" Edipon asked, forgetting the knife for the moment, drawn on by the joys of a technical discussion.

"That\'s what I thought. I can see where your bootleg joyjuice is going to take a big jump in quality, if you have anyone here who can do some simple glassblowing. Though it might be easier to rig up a coiled bi-metallic strip. You\'re trying to boil off your various fractions, and unless you keep an even and controlled temperature you are going to have a mixed brew. The thing you want for your engines are the most volatile fractions, the liquids that boil off first like gasoline and benzene. After that you raise the temperature and collect kerosene for your lamps and so forth right on down the line until you have a nice mass of tar left to pave your roads with. How does that sound to you?"

Edipon had forced himself into calmness, though a jumping muscle in his cheek betrayed his inner tension. "What you have described is the truth, though you were wrong on some small things. But I am not interested in your thermometer nor in improving our water-of-power, it has been good enough for my family for generations and it is good enough for me...."

"I bet you think that line is original?"

"... There is something that you might be able to do that would bring you rich rewards. We can be generous when needs be. You have seen our caroj and ridden on one, and seen me go into the shrine to intercede with the sacred powers to make us move. Can you tell me what power moves the caroj?"

"I hope this is the final exam, Edipon, because you are stretching my powers of extrapolation. Stripping away all the shrines and sacred powers I would say that you go into the engine room to do a piece of work with very little praying involved. There could be a number of ways of moving those barns, but let\'s think of the simplest. This is top of the head now, so no penalties if I miss any of the fine points.

"Internal combustion is out, I doubt if you have the technology to handle it, plus the fact there was a lot to do about the water tank and it took you almost an hour to get under way. That sounds like you were getting up a head of steam—the safety valve! I forgot about that. So it is steam. You go in, lock the door of course, then open a couple of valves until the fuel drips into the firebox, then you light it. Maybe you have a pressure gauge, or maybe you just wait until the safety valve pops to tell you if you have a head of steam. Which can be dangerous since a sticking valve could blow the whole works right over the mountain.

"Once you have the steam you crack a valve to let it into the cylinders and get the thing moving. After that you just enjoy the trip, of course making sure the water is feeding to your boiler all right, that your pressure stays up, your fire is hot enough, all your bearings are lubricated and the rest...."

Jason looked on astounded as Edipon did a little jig around the room, holding his robe up above his bony knees. Bouncing with excitement he jabbed his knife into the table top and rushed over to Jason and grabbed him by the shoulders, shaking him until his chain rattled.

"Do you know what you have done?" he asked. "Do you know what you have said?"

"I know well enough. Does this mean that I have passed the exam? Was I right?"

"I don\'t know if you are right or not. I have never seen the inside of one of the Appsalan devil-boxes." He danced around the room again. "You know more about their ... what do you call it, engine ... than I do. I have only spent my life tending them and cursing the people of Appsala who keep the secret from us. But you will reveal it to us! We will build our own engines and if they want water-of-power they will have to pay dearly for it."

"Would you mind being a little bit clearer," Jason pleaded. "I have never heard anything so confused in my entire life."

"I will show you, man from a far world, and you will reveal the Appsalan secrets to us. I see the dawn of a new day for Putl\'ko arriving." He opened the door and shouted for the guards, and for his son, Narsisi, who arrived as they were unlocking Jason who recognized him as the same droop-eyed and sleepy looking D\'zertano who had been helping Edipon to drive their ungainly vehicle.

"Seize this chain my son and keep your club ready to kill this slave if he makes any attempt to escape. Otherwise do not harm him, for he is very valuable. Come."

He tugged on the chain, but Jason only dug his heels in and did not move. They looked at him, astonished.

"Just a few things before we go. The man who is to bring the new day to Putl\'ko is not a slave, let us get that straight before this operation goes any further. We\'ll work out something with chains or guards so I can\'t escape, but the slavery thing is out."

"But—you are not one of us, therefore you must be a slave."

"I\'ve just added a third category to your social order. Employee. Though reluctant, I am still an employee, skilled labor, and I intend to be treated that way. Figure it out for yourself. Kill a slave and what do you lose? Very little if there is another slave in the pens that can push in the same place. But kill me and what do you get? Brains on your club—and they do you no good at all there."

"Say, Dad, does he mean I can\'t kill him?" Narsisi looked puzzled as well as sleepy.

"No, he doesn\'t mean that. He means if we kill him there is no one else that can do the work he is to do for us. I can understand him and I do not like it. There are only slaves and slavers, anything else is against the natural order. But he has us trapped between satano and the sand-storm so we must allow him some freedoms. Bring the slave now ... I mean the employee ... and we will see if he can do the things he has promised. If he does not, I will have the pleasure of killing him because I do not like his revolutionary ideas."

They marched single file to a locked and guarded building with immense doors, which were pulled open to reveal the massive forms of seven caroj.

"Look at them," Edipon hissed and tugged at his nose. "The finest and most beautiful of constructions, striking fear into our enemies\' hearts, carrying us fleetly across the sands, bearing on their backs immense loads and only three of the things are able to move."

"Engine trouble?" Jason asked lightly.

Edipon grumbled, cursed and fumed under his breath and led the way to an inner courtyard where stood four immense black boxes painted with death-heads, splintered bones, fountains of blood and cabalistic symbols all of a sinister appearance.

"Those swine in Appsala take our water-of-power and give nothing in return. Oh yes, they let us use their engines, but after running for a few months the cursed things stop and will not go again, then we must bring them back to the city to exchange for a new one, and pay again and again."

"A nice racket," Jason said, looking at the sealed covering on the engines. "Why don\'t you just crack into them and fix them yourself, they can\'t be very complex."

"That is death!" Edipon gasped, and both D\'zertanoj recoiled from the boxes at the thought. "We have tried that, in my father\'s father\'s day, since we are not superstitious like the slaves and know that these are man-made not god-made. However the tricky serpents of Appsala hide their secrets with immense cunning. If any attempt is made to break the covering horrible death leaks out and fills the air. Men who breathe the air die, and even those who are solely touched by it develop immense blisters and die in pain. The man of Appsala laughed when this happened to our people and after that raised the price even higher."

Jason circled one of the boxes, examining it with interest, trailing Narsisi behind him at the end of the chain. The thing was higher than his head and almost twice as long. A heavy shaft emerged through openings on opposite sides, probably the power takeoff for the wheels. Through an opening in the side he could see inset handles and two small colored disks, and above this were three funnel-shaped openings shaped and painted like mouths. By standing on tiptoe Jason looked on top but there was only a flanged, sooty opening that must be for attachment of a smokestack. There was only one more opening, a smallish one in the rear, and no other controls on the garish container.

"I\'m beginning to get the picture, but you will have to tell me how you work the controls."

"Death before that," Narsisi shouted. "Only my family—"

"Will you shut up!" Jason shouted right back. "Remember? You\'re not allowed to browbeat the help anymore. There are no secrets here. Not only that, but I probably know more about this thing than you do just by looking at it. Oil, water and fuel go in these three openings, you poke a light in somewhere, probably in that smoky hole under the controls, open one of those valves for fuel supply, another one is to make the engine go slower and faster, and the third is for your water feed. The disks are indicators of some kind." Narsisi paled and stepped back. "So keep the trap shut while I talk to your dad."

"It is as you say," Edipon pointed. "The mouths must always be filled and woebetide if they shall go empty for the powers will halt or worse. Fire goes in here as you guessed, and when the green finger comes forward this lever may be turned for motion. The next is for great speed or going slow. The very last is under the sign of the red finger, which when it points indicates need, and the handle must be turned and held until the finger retires. White breath comes from the opening in back. That is all there is."

"About what I expected," Jason muttered and examined the container wall, rapping it with his knuckles until it boomed. "They give you the minimum of controls to run the thing, so you won\'t learn anything about the basic principles involved. Without the theory you would never know what the handles control, or that the green indicator comes out when you have operating pressure or the red one when the water level is low in the boiler. Very neat. And the whole thing sealed up in a can and booby-trapped in case you have any ideas of going into business for yourself.

"The cover sounds like it is double walled, and from your description I would say that it has one of the vesicant war gases, like mustard gas, sealed inside there in liquid form. Anyone who tries to cut their way in will quickly forget their ambitions after a dose of that. Yet there must be a way to get inside the case and service the engine, they aren\'t just going to throw them away after a few months\' use. And considering the level of technology displayed by this monstrosity I should be able to find the tricks and get around any other built-in traps. I think I\'ll take the job."

"Very well, begin."

"Wait a minute, boss, you still have a few things to learn about hired labor. There are always certain working conditions and agreements involved, all of which I\'ll be happy to list for you."