Plight on cue, the discreet hum that had been coming from the very modern engine of the caravan transporter turned suddenly harsh. A second later the engine died completely. The rolling wheels, simple machines indeed, supporting all the cars, still whispered smoothly. The train of wagons coasted quietly for a few more meters, long enough to carry them all into the invisible breakdown zone, then rolled to a dead stop. The driver, accustomed to this phenomenon, had calculated his speed nicely just before the engine died.

A few passengers noted that a similar fate had overtaken a few small items of modern equipment they had been carrying with them.

A young crewman was announcing: "We'll be under way again in just a few minutes, people."

How are we going to do that? Harry wondered. With everything else he'd had to think about, he hadn't got around to really pondering that question yet. But now it seemed he was about to find out. Disembarking from the wagon with Bulaboldo and Lily, he watched the majority of the passengers go scrambling on ahead. He stood there, boots crunching on this truly alien soil, and waited to see what would happen next. This couldn't be the caravanserai, the scheduled overnight stop; by Harry's calculations, that was still about a hundred kilometers to the east.

Right here there was nothing like a hotel in sight, only a peculiar structure the size of a small garage, but looking more like a corral or cage, made of loosely interwoven strips of tough and slippery imported material. The corral enclosed some ten or a dozen spheres like those that he had earlier seen rolling free across the landscape.

Harry decided he wasn't going to ask what happened next. He'd doubtless find out soon enough.

The people of the train's crew had opened up the cage and were somehow urging or prodding the captive spheres to leave it, talking to them meanwhile as if encouraging animals. The creatures, things, whatever they were, looked like so many neatly carved and polished boulders, seemingly formed of the same material as the land. But they were true spheres, mathematically perfect as far as Harry's eye could tell.

Bulaboldo, standing with his arms folded, was watching something he had seen a dozen times before, just waiting for this preparation, whatever it was, to be over, so he could get on with his business trip.

Harry gave up and asked. "What's going on?"

"They're just hitching up the team, old lad. Supplying our motive power for the next leg of the journey."

"Hitching up the team?"

Lily said: "I was wondering if we had to walk the rest of the way, pushing the wagons." And then, half seriously, she began murmuring her mantra: "This is not a planet. This is not a planet..."

How heavy the big spheres might be was hard to tell. The train crew, pushing moderately hard, seemed to have little trouble rolling and prodding them, one at a time, out of their roadside cage and into a lighter kind of inverted cage that had been dragged out from somewhere and attached to the front of the caravan, from which the transporter engine had been disconnected.

Now and then during this process, the spheres showed a tendency for spontaneous movement.

Harry was fascinated. "Damn. Then your rollers are alive?"

Kul shook his head. "I don't think so. No one's ever seen them eat, or die, or reproduce. The theory is that they draw their energy from the ground, somehow. The transport company does hear a complaint, now and then, from some society for the prevention of cruelty to animals."

"I take it that they're native here. Just look at them, they have to be."

"They're native. Catching wild rollers, which is the local term, is something of an adventure. Essentially, one has to chase them down on foot."

"I bet."

A crew member moved among the passengers, making sure everyone understood that the rest of the day's journey would be accomplished much more slowly. It would take five hours to travel the hundred kilometers between the changeover spot and the caravanserai, their lodging for the coming night. Meanwhile, the rest of the crew went expertly about the task of getting the transporter out of the way. Since the transporter's engine had entirely ceased to function, several willing and active passengers were enlisted to help - Harry did, Kul managed to avoid the effortwith the tugging and pushing required to move the powered unit to one side of the main road, and swing it completely around so its decorated nose pointed back in the direction of Port City. Dragging the useless engine deep into the breakdown zone and out again would serve no purpose.

Harry would have liked to open up some cowling and take a close look at the idled engine, to try to pin down exactly where the failure had been induced. But he was no expert in such machines, no one else seemed to have a similar idea, and he was reluctant to draw attention to himself.

The body of the transporter was constructed of very light materials, so turning it front to back was easy enough after the boxes and bags of freight had been unloaded from the lower level, and reloaded on the lightweight sphere-drawn engine that took the transporter's place. The wagons also were very light minus the freight most of them were carrying; had there been any wind, it would doubtless have been enough to set the empty wagons rolling.

When the movable cage and its population of spheres (Harry hoped they were rested and ready for a day's work, whether or not they were alive) had been attached at the front of the train, and everyone was aboard, a small, glassy bowl filled with some flammable material was set alight, then placed in a sling set dangling at the end of a long pole. The driver had taken his usual place, but was using an entirely different set of controls.

Again Bulaboldo was explaining. "The spheres, you see, respond to a particular spectrum of radiation. The flame provides it."

Whatever the exact mechanism, the fire was undoubtedly attractive. The caged spheres began a concerted movement. Pushing against the front wall of the cage, which was evidently made of some almost frictionless material, they exerted a force that moved the loaded wagons. Their collective movements in the cage produced a distinctive, polyphonic noise, something between faint whistling and light scraping.

"I don't believe it," Harry murmured. He was back in his comfortable chair, once more watching the landscape as it rolled past. As they had been warned, their speed was much reduced. But it held steady.

"This is not a planet," Lily sweetly reminded him.

The driver was steering, keeping the train of wagons on the road, by swinging the lure of the attractive light to left or right as necessary. There didn't seem to be anything in the way of a speed control in use, but Harry supposed that if you quenched the fire in the lure, or moved it to where the spheres could not detect its glow, they'd stop.

He was still staring at the spheres. "Do they die? Are they born?"

Kul said: "As to how they come into existence, there are different theories. No one has ever observed the process. An individual roller eventually stops rolling, or so I'm told, and after that gradually blends back into the landscape. Some people consider that just about equivalent to what happens to us."

"What if you cut one open? Break it up?"

"I'm told you don't find any internal organs, only a practically homogeneous interior. Cut it in pieces, and all you have is a pile of Maracandan soil."

Lily said: "I've read something about them. The general consensus seems to be that they're moving landforms. They draw energy from some kind of field that permeates Maracandan space - here in the habitable zone, at least."

Harry asked: "The same field that creates the breakdown zones?"

Kul shrugged. "Probably related somehow. But you're asking the wrong fellow. I'm sure the boffins can show you pages of mathematics."

There seemed no way of communicating with the rolling landforms. Scores, if not hundreds, of people had tried that, some using truly imaginative methods. No one had had any success. The spheres were what they were, and did what they did, and that was that.

At last Harry said: "I know one way to tell whether they're alive or not."

"What's that, dear fellow?"

"Put them in front of a berserker, and it'll quickly take the decision out of your hands."

Moving more slowly made it easier to study the passing scenery. Now Harry noticed that the warning signs were made of imported wood, like the little fingerposts that marked the road. And Bulaboldo pointed out how these, too, were starting to be blurred and degraded by their strange environment, by an infiltration of the land itself. The patterns of the land were reproducing themselves in alien material. Wood, for some unknown reason, seemed most resistant to the gradual transformation.

And here, again, something like a reverse process was at work. The land in turn seemed to borrow patterns from certain kinds of imported wood.

Bulaboldo seemed to enjoy lecturing. "The first people to move here more or less permanently were researchers, who were simply delighted when they found stable conditions that allowed them to land - a truly habitable zone, even air that allowed them to take their helmets off, for a few breaths. The original, primitive atmosphere wasn't as good as the gravity, but it was close to the mark. It just cried out to be augmented."

Harry was shaking his head. "I still don't get it. Whatever these forces are, that disable advanced technology - how do they decide what counts as an advanced machine? A lot of complicated machines are only combinations of simple ones."

Bulaboldo shrugged. "Talk to a boffin about it - I've tried - and he or she will snow you solemnly with advanced math, dealing with extreme complexity. But you won't hear any real answer. No doubt the great brains of the human race will figure Mara-canda out for us someday. Probably not until they resurrect some way of doing science that doesn't depend entirely on computers and elaborate gadgets. Currently, they have a hard time measuring anything at all inside a breakdown zone.

"There were some early settlers who were just fascinated by the idea of living in a place where machines refused to operate, who imported genengineered horses and camels to carry riders and pull loads. Didn't work, though."

"Why not?"

"Didn't see it tried myself, but they say it was very difficult to feed the creatures properly, importing and recycling food. Anyway, the animals tended to sicken and die - which people here do not, by the way. It's quite a healthy environment for humanity - as long as we make sure the water and air and food are up to standard."

The train was equipped with a few small oil-burning lamps, for those times when it was necessary to get through a breakdown zone in darkness. Just in case, as Bulaboldo explained, night should fall while the caravan was still on the road.

"There's another point I can't even begin to understand, that is why Maracanda should have night and day. This so-called habitable body doesn't spin like a planet. And even if it did, it's not exposed to anything like normal sunlight - "

"All I know is, the authorities say the illumination conies from some - some interaction between the layers of the sky. As to why it's gradually taking on the timing of some Earth-like planet's diurnal cycle - probably that of Earth itself..." The big man shrugged.

"But there's no doubt that's what it's doing?"

"So the records indicate."

Harry shook his head, marveling.

"The Malako people, and several other cults, have explanations for it all. But there's nothing on a scientific level."

"I wonder," said Lily softly, "that people dare to live here at all. And even to raise children. I'd be wary of bringing mine to a place like this."

Harry was curious. "You have any?"

She shook her head. "Alan and I have made plans - No, I've made plans from time to time, and tried to get him to agree. But he's always got something else... Things keep coming up." Her hand gestured back and forth, like someone trying to clear a fog.

"Our lives just haven't allowed for any stability. You must know how that is."

Harry grunted. Back in Port City, waiting in Rovaki's outer office, he had heard the newscaster saying something about a new school being opened.

Dusk was deepening into night as a low, sprawling, palisaded building that could only be the caravanserai came into view ahead.

Harry asked one of the train crew. "Do we get a break from the breakdown zone here?"

"Not much of one, I'm afraid. There are a few square meters of free zone near the center of the building, but they're taken up almost entirely by a compact food-and-drink recycler and a public telegraph station."

Harry, for whatever reason, had been expecting the overnight accommodation to be a small, crude structure. But its single story, the outer wall a palisade of imported logs, sprawled over half a hectare or so of ground.

The walls were twice as high as a man, and appeared to have been fashioned from the same imported material - logs - as the telegraph poles. This gave the place the look of some ancient stockade, an effect spoiled by the numerous broad, low windows that had been cut in the walls, openings defended only by ornamental metal grillwork. Several doorways were broad and undefended, too.

But then, who was going to attack?

The caravan stopped some twenty meters from the building, at just a little distance off the road.

The place seemed large enough to house all the passengers and crew of a large caravan in reasonable comfort, but word was that tonight all the sleeping rooms were going to be taken.

Harry noted that the telegraph cable went right in through a small hole in one rugged wall, to come out again on the far side of the building, and run into the distance beside the road.

Harry and his two traveling companions paused, a little way outside the compound, to watch the last bright glow of sunset - well, something vaguely like a sunset, Harry thought, a streakiness of light, and changing colors.

"This is the first time," Lily said softly, "I've ever seen a sunset without a sun."

Leaving his companions behind for a time, Harry went scouting on his own, stretching his legs. Ordinarily he might have gone wandering off alone into the Maracandan back country, which was perfectly safe, by all accounts, as long as you didn't stay lost for so long that you died of thirst, and you didn't fall into one of the rare subduction zones, where the surface of the world was slowly drawn underground, to be eventually produced again somewhere else. But right now he stayed in sight of the building, wanting to keep an eye on Kul as much as possible - and on Lily Gunnlod as well.

A large common room, lighted pleasantly by thick candles and brightened by the many mirrors on its walls, formed part of the interior of the caravanserai. One side of this space did duty as a kind of general store, with two clerks behind a counter conducting business - cash only, please - computing prices and change with an abacus. Here Harry soon provided himself with a change of clothes, as well as a shaver and a toothbrush.

Carrying his purchases in a small bag, he let his curiosity lead him next to inspect the telegraph facility. This was a small room partitioned off from the large common interior space, advertising its presence by the wash of modern light coming over and under and around the barrier. Someone had marked the boundaries of the hostel's central live zone with paint. The fiberoptic lines of the public telegraph came into the small island of free zone from both east and west, to be connected to a bright brass-colored manual key. Harry didn't suppose that the Templars had any terminal here - no loss, because he had no message for General Pike anyway.

In the middle of the telegraph room, a simple machine very much like the one Harry had seen at Templar headquarters converted the impulse of distant keystrokes to pulses of light and then displayed them on a kind of printout.

Bulaboldo strolled into the telegraph room, nodded casually to Harry, and asked if there were any messages for him. The civilian operator sitting at the table checked a list, then shook his head.

At one side of the small free-zone space, a couple of technicians sat and squatted on the floor, surrounded by a small scattering of modern tools. They were steadily tinkering with some elaborate, low-mounted gadget that was connected by lines to the telegraph, though evidently not part of it.

Bulaboldo, not finding any messages, was gone again. Harry lingered, striking up a conversation with the technicians.

"Strange world, eh? Some strange machinery."

One of the men on the floor chuckled. He seemed ready to take a break in his struggle with a small tool that was refusing to perform. He sat back and popped a chewing pod into his mouth. "I guess you might call it that. But what can you expect from a place that has huge chunks of antimatter in its core?"

Harry squinted at him. "It has huge... what?"

The second worker, still trying to puzzle out his job, was shaking his head and smiling. The first technician grinned. "Fact. Only a couple of hundred meters below us as we sit here, the rocks go crazy, turning into layers of shit like you wouldn't believe. Among the other goodies there are antimatter capsules, mostly bundled antineutrons, several tons in a package, neatly wrapped up in what seems to be a permanent magnetic binding."

Harry was staring at the man. Anywhere else in the Galaxy, he would have been certain that his leg was being pulled. Here on Maracanda, all he could say was "I don't see how it's possible."

The tech seemed pleased to have shared a marvel. "We come back to the usual Maracandan explanation: 'Balance of forces.' That's what the scientists tell us. Seems to cover just about everything."

Harry said: "I'd like to talk to one of the scientists. One who's really working to understand the peculiarities of this place."

The second tech looked up from his work at last. "Well, you just missed your chance. Fellow who passed through just yesterday, came in here and wanted to see all our latest readings. Tom, what was his name? Cloberg, something like that."

Tom wasn't quite sure either. "But I know there's quite a large staff, at the research station over in Minersville." The tech's jaws worked, grinding the last remnant of the chewing pod to juice.

Meanwhile, Harry had been running his gaze over the telegraph instrument. The key chattered now and then, as if talking to itself, and wrote out light streaks on a slowly revolving drum, where sensitive paper recorded the coded messages.

The operator displayed a message. He seemed pleased, as at a rare discovery. "Here's one that looks intact. Maybe it makes sense."

Number One tech, still sitting on the floor, shook his head. "Maybe not. If you do decode a lot of them, you realize that some were transmitted years ago."

If Harry had been anywhere else, he wouldn't have been tempted to believe that.

It was time to prepare for dinner. After a visit to the row of chemical toilets, much like the units aboard the caravan, Harry washed his hands and face at one of the adjoining sinks.

Since nearly all of the caravanserai was in a breakdown zone, maintenance machines were disqualified from cleaning the toilets and performing the hundred other tasks of daily housekeeping. Live workers had been found for the jobs, and doubtless were well paid.

Dinner in the common room at the caravanserai came close to living up to Bulaboldo's recommendation. The resident human chef was something of a virtuoso in his use of the recycler, a unit almost as up to date as Harry's in the Witch. There was also some interesting talk, with the stationmaster and members of the train crew joining passengers at table.

It occurred to Harry, looking at the glow of electric light washing out of the free-zone room, that this might be the strange part of the universe, the portion where high tech and high science can be made to work. For all that humanity had discovered so far, the bulk of the Galaxy, and all the endless galaxies beyond, could be pure breakdown zone.

Within the small enclave of human presence, buried deep in Maracandan night, gas lamps, or oil lamps, gave a warm but faintly flickering, cheerful illumination. Outside the circle of the flames' illumination, a blackness of frightening intensity had come over the silent land.

After dinner and a brief walk around the compound, Harry retreated to his small assigned room, where he lit the single candle waiting on its stand, took off only his boots, and lay down in his spacefarer's coveralls on one of the room's two cots.

Bulaboldo's room was down the hall somewhere. Lily had the small room next to Harry's, and she retired at about the same time Harry did. He was still trying to keep half an eye on her, though more and more it seemed like totally wasted effort. The suspicion planted by the smugglers in the space station was very nearly dead, but still retained a breath of life in Harry's mind. He wanted to see if this woman and Bulaboldo were secretly in some kind of partnership, or if she might be going to meet some other coconspirator, and have a long and secret talk.

Stretching out on the cot, Harry was glad that the sleeping rooms were roofed. He assumed this had been done only for privacy, but there might have been other reasons. Blowing out his candle, he thought that he would much rather lie exposed to a natural planetary sky than to the continual dull overhead of Maracanda, beyond which something, something no human had yet managed to understand, ceaselessly played at counterfeiting day and night. Without a roof he might have been afraid to close his eyes. As if some unwelcome presence might come dropping out of that gray nothingness...