“Please forgive the hiatus. What have you decided to do?”

“Explore,” Chmeee said curtly. He turned back to the lander.

“Give me details. I am not happy about risking one of my probes merely to maintain communications. The primary purpose of these probes was to refuel Needle.”

“Return your probe to safety,” Chmeee told the puppeteer. “When we return we will report in full.”

The probe settled onto the rim wall on several small jets. It was a lumpy cylinder twenty feet long. The Hindmost said, “You speak frivolously. It is my landing craft you risk. Do you plan to search the base of the rim wall?”

That thrilling contralto, that lovely woman’s voice, was the same that every puppeteer trader had learned from his predecessor. Possibly they learned another to influence women. To men it was a voice that pushed buttons, and Louis resented that. He said, “There are cameras on the lander, aren’t there? Just watch.”

“I have your droud. Explain.”

Neither Louis nor Chmeee bothered to answer.

“Very well. I have locked open the stepping-disc link between the lander and Needle. The probe will function as a relay for this, too. As for your droud, Louis, you may have it when you learn to obey.”

And that, thought Louis, defined his problem nicely.

Chmeee said, “It is good to know that we can flee our mistakes. Are there range limits to stepping discs?”

“Energy limits. The stepping-disc system can absorb only a limited kinetic energy difference. Needle and the lander should have no relative velocity when you flick across. You are advised to stay directly to port of Needle.”

“This fits our plans.”

“But if you abandon the lander, I still control your means of escape from the Ringworld. Do you hear me, Chmeee, Louis? The Ringworld will impact the shadow squares in just more than Earth’s year.”

Chmeee lifted the lander on puppeteer-developed repulsers. A burst from the aft fusion motor edged the craft forward and off the edge.

Flying on Ringworld-floor-material repulsers was not like using antigravity, Louis noted. Repelled by both the rim wall and the landscape, the lander fell in a swooping curve. Chmeee stopped their descent at forty miles.

Louis displayed a telescope view on one of the screens. Floating on repulsers alone, above most of the atmosphere, the lander was very steady and utterly quiet: a good telescope mount.

Rocky soil lapped up in foothills to the base of the rim wall. Louis ran the telescope slowly along that border, at high magnification. Barren brown soil against glassy gray. An anomaly would be easy to spot.

“What do you expect to find?” Chmeee asked.

Louis didn’t mention the watching puppeteer, who thought they were searching for an abandoned transmutation device. “A spacecraft crew would have come through from the spaceport ledge about here. But I don’t see anything big in the way of abandoned machinery. We aren’t really interested in little stuff, are we? They wouldn’t have left anything valuable unless it was just too tanj big to move, and then they’d have left almost everything they had.”

He stopped the telescope. “What do you make of that?”

It stood thirty miles tall against the base of the rim wall: a half-cone, with a weathered look, as if smoothed by a hundred million years of wind. Ice glittered in a broad belt around its lower slope. The ice was thick and showed the flow patterns of glaciers.

“The Ringworld imitates the topography of Earthlike worlds,” said Chmeee. “From what I know of Earthlike worlds, this mountain doesn’t fit the pattern.”

“Yah. It’s inartistic. Mountains come in chains, and they aren’t this regular. But, you know, it’s worse than that. Everything on the Ringworld is contoured in. Remember when we took the Liar underneath? Sea bottoms bulging, dents for mountains and gullies for mountain ranges, riverbeds like veins in a weight lifter’s arm? Even the river deltas are carved into the structure. The Ringworld isn’t thick enough to let the landscape carve itself.”

“There are no tectonic processes to do the carving, for that matter.”

“Then we should have seen that mountain from the back, from the spaceport. I didn’t. Did you?”

“I’ll take us closer.”

That turned out to be difficult. The closer the lander came to the rim wall, the more fusion thrust was needed to hold it there … or to lift the lander if the repulsers were turned off.

They came within fifty miles, and that was close enough to find the city. Great gray rocks protruded through the ice floes, and some of these showed myriad black-shadowed doors and windows. Focus closer and the doorways had balconies and awnings, and hundreds of slender suspension bridges ran up, down, and sideways. Stairways were hacked into the rock; they ran in strange branching curves, half a mile tall and more. One dipped all the way to the foothills, to the tree line.

A fortuitous flat space in the center of the city, half rock and half permafrost, had become a public square; the hordes that thronged it were pale golden flecks just big enough to see. Golden clothing or golden fur? Louis wondered. A great boulder at the back of the square had been carved with the face of a hairy, chubby, jovial baboon.

Louis said, “Don’t try to get closer. We’ll scare them away if we try to land on fusion drive, and there isn’t any other way.”

A vertical city with a population of ten thousand, at a guess. Deep-radar showed that they had not dug deep into the rock. In fact, those rocks riddled with rooms looked like dirty permafrost.

“Surely we want to question them regarding their peculiar mountain?”

“I’d love to talk to them,” Louis said, and he meant it. “But look at the spectrograph and deep-radar. They don’t use metals or plastics, let alone single-crystal stuff. I hate to think what those bridges are made of. They’re primitives. They’ll think they’re living on a mountain.”

“I agree. Too much trouble to reach them. Where next? The floating city?”

“Yah, by way of the sunflower patch.”

A shadow square was sliding across the sun’s disc.

Chmeee lit the aft motor again and ran their speed to ten thousand miles per hour, then coasted. Not too fast for detail, but fast enough to get them where they were going in about ten hours. Louis studied the racing landscape.

In principle the Ringworld should have been an endless garden. It was not a randomly evolved world, after all, but a made thing.

What they had seen on their first visit could not be considered typical. They had spent most of their time between two big meteoroid punctures: between the eye storm, which was spewing air through a puncture in the Ringworld floor, and the stretched and raised landscape around Fist-of-God Mountain. Of course the ecology was damaged. The engineers’ carefully planned wind patterns must have been ruined.

But here? Louis looked in vain for the pattern of an eye storm, a hurricane turned on its side and flattened. There were no meteoroid punctures here. Yet there were patches of desert, Sahara-size and larger. On the ridges of mountain ranges he found the pearly gleam of naked Ringworld foundation. Winds had stripped away the covering rock.

Had the weather patterns grown this bad, this fast? Or did the Ringworld engineers like deserts? It struck Louis that the Repair Center must have been deserted for a very long time. Halrloprillalar’s people might never have found it at all, after the Ringworld engineers vanished. As they had to have vanished, if Louis’s guess was right.

“I want three hours’ sleep,” Chmeee said. “Can you fly the lander if something happens?”

Louis shrugged. “Sure, but what could happen? We’re too low for the meteor defense. Even if it’s based on the rim wall, it’d be firing on settled land. We’ll just cruise awhile.”