"Tree-of-life doesn't grow right without a soil additive: thallium oxide. Thallium must be more common in the galactic core than it is out here. Wherever the protectors spent a lot of their time, we'll find thallium oxide for the plants. That's how we'll find the repair center. We'll go in in pressure suits, if we ever get that far."

Chapter 14 -.

The Scent of Death The Hindmost's voice exploded at them as they reached the road. "... LANDER! CHMEEE, LOUIS, WHAT ARE YOU HIDING? HINDMOST CALLING THE LAND-"

"Stop! Tanj dammit, turn down the volume, you'll blow our ears out!"

"Can you still hear me?"

"We can hear you fine," said Louis. Chmeee's ears had folded into pockets of fur. Louis was wishing he could do that. "The mountains must have blocked us."

"And what was it you discussed while we were cut off?"

"Mutiny. We decided against it."

A momentary pause; then "Very wise," said the Hindmost. "I want your interpretation of this hologram."

One of the screens showed a kind of bracket poking out from the rim wall. The picture was slightly blurred, and oddly lit: taken in vacuum, in sunlight and light reflected from the Ringworld landscape on the right. The bracket seemed to be of a piece with the rim wall itself, as if scrith had been stretched like taffy. The bracket held a pair of washers or doughnuts separated by their own diameter. Nothing else showed save the top of the rim wall. It was impossible to guess the scale.

"This was taken from the probe," the puppeteer said. "I have inserted the probe into the rim transport system, as advised. It is accelerating to antispinward."

"Yeah. What do you think, Chmeee?"

"It might be a Ringworld att.i.tude jet. It would not be firing yet."

"Maybe. There are a lot of ways to design a Bussard ramjet. Hindmost, do you get anything in the way of magnetic effects?"

"No, Louis, the machine seems dormant."

"The superconductor plague wouldn't have touched it in vacuum. It doesn't look damaged. The controls could be somewhere else, though. On the surface. Maybe they can be repaired."

"You would have to find them first. In the Repair Center?"

"Yeah."

The road ran between swampland and stony highlands. They pa.s.sed what looked like another chemical plant. They must have been seen; there was a deep-throated foghorn sound and a blast of steam from what might have been a chimney. Chmeee didn't slow down.

They saw no more of the boxy vehicles.

Louis had seen pale glimmers pa.s.sing slowly among the trees, far into the swamp. They moved as slowly as mist on water, or as ocean liners docking. Now, far ahead, a white shape moved free of the trees and toward the road.

From a vast white bulk the beast's sense-cl.u.s.ter rose on a slender neck. Its jaw was at ground level; it dropped like a shovel blade, scooping up swamp water and vegetation as the beast cruised uphill on rippling belly muscles. It was bigger than the biggest dinosaur.

"Banders.n.a.t.c.h," Louis said. What were they doing here? Banders.n.a.t.c.hi were native to Jinx. "Slow down, Chmeee, it wants to talk to us."

"What of it?"

"They've got long memories."

"What would they remember? Swamp dwellers, muck-eaters, without hands to make weapons. No."

"Why not? Maybe they could tell us what banders.n.a.t.c.hi are doing on the Ringworld in the first place."

"That is no mystery. The protectors must have stocked their maps in the Great Ocean with samples of the species they considered potentially dangerous."

Chmeee was playing dominance games, and Louis didn't like it. "What's the matter with you? We could at least ask!"

The banders.n.a.t.c.h dwindled behind them. Chmeee snarled, "You avoid confrontation like a Pierson's puppeteer. Questioning muck-eaters and savages! Killing sunflowers! The Hindmost brought us to this doomed structure against our wills, and you delay our vengeance to kill sunflowers. Will it matter to the Ringworld natives a year from now that Louis the G.o.d paused in his pa.s.sing to pull weeds?"

"I'd save them if I could."

"We can do nothing. It is the road builders we want. Too primitive to threaten us, advanced enough to know answers to questions. We will find an isolated vehicle and swoop down on it."

In midafternoon Louis took over the flying.

The swamp became a river that arched away to spinward, wide of its original bed. The crude road followed the new river. The original bed ran more nearly to port, in careful S-curves, with an occasional stretch of rapids or waterfall. It was dry as bone, running into bone-dry desert. The swamp must have been a sea before it silted up.

Louis dithered, then followed the original bed.

"I think we've got the timing right," he told Chmeee. "Prill's people evolved long after the engineers were gone. Of all the intelligent races here, they were the most ambitious. They built the big, grand cities. Then that odd plague knocked out most of their machinery. Now we've got the Machine People, and they could be the same species. The Machine People built the road. They did it after the swamp formed. But I think the swamp formed after Prill's people's empire collapsed.

"So what I'm doing is looking for an old Prill People city. We could get lucky and find an old library or a map room."

They had found cities scarce during the first expedition. Today they traveled for some hours without seeing anything except, twice, a cl.u.s.ter of tents, and once, a sandstorm the size of a continent.

The floating city was still ahead of them, edge on, hiding detail. A score of towers reared around the edge; inverted towers dropped from nearer the center.

The dry river ended in a dry sea. Louis cruised along the sh.o.r.e, twenty miles up. The sea bed was strange. It was quite flat, except where artfully s.p.a.ced islands with fluted edges rose from the bottom.

Chmeee called, "Louis! Set us on autopilot!"

"What have you found?"

"A dredge."

Louis joined Chmeee at the telescope.

He had taken it for part of one of the bigger islands. It was huge and flat, disc-shaped, the color of seabottom mud. Its top would have been below sea level. Its seamless rim was angled like the blade of a wood planer. The machine had stalled up against the island it had dredged from the sea bottom.

So this was how the Ringworld engineers had kept the sludge flowing into the spillpipes. It wouldn't flow of itself; the sea bottoms were too shallow. "The pipe blocked," Louis speculated. "The dredge kept going till it broke down, or till something cut the power-something like the superconductor plague. Shall I call the Hindmost?"

"Yes. Keep him satisfied ..."

But the Hindmost had bigger news.

"Observe," he said. He ran a quick succession of holograms on one of the screens. A bracket poked up and out from the rim wall, with a pair of toroids mounted at its tip. Another bracket, seen from farther away; and in this picture a spill mountain showed at the foot of the rim wall. The spill mountain was half the size of the bracket. A third bracket showed. A fourth, with structures next to it. A fifth-"Hold it!" Louis cried. "Go back!"

The fifth bracket stayed on the screen for a moment. Its tip held nothing at all. Then the Hindmost flipped back to the fourth hologram.

It was somewhat blurred by the probe's velocity. There was heavy lifting machinery anch.o.r.ed to the rim wall next to the bracket: a crude fusion generator; a powered winch; a drum and a hook floating unsupported below it. The cable depending from the drum must be invisibly thin, Louis thought. It could be shadow square wire.

"A repair team already at work? Uurrr. Are they mounting att.i.tude jets or dismounting them? How many are mounted?"

"The probe will tell us," the Hindmost said. "I direct your attention to another problem. Recall to your mind those toroids that circle the waist of the one intact Ringworld s.p.a.cecraft. We surmise that they generate the electromagnetic scoop fields for Bussard ramjets."

Chmeee studied the screen. "The Ringworld ships were all of the same design. I wondered why. You may be right."

Louis said, "I don't understand. What has-"

Two one-eyed snakes looked out of a screen at him. "Halrloprillalar's species built part of a transportation system that would give them endless room to colonize and explore. Why didn't they continue? All of the Ringworld was theirs through the rim transport system. Why would they make the effort to reach the stars?"

It made an ugly pattern. Louis didn't want to believe it, but it fit too well. "They got the motors for free. They dismounted a few of the Ringworld att.i.tude jets, built ships around them, and reached the stars. And nothing went obviously wrong. So they dismounted a few more. I wonder how many they used."

"The probe will tell us in time," the puppeteer said. "They seem to have left a few motors still mounted. Why did they not move the Ringworld back into position before the instability grew so great? Chmeee's question is a good one. Are motors being remounted, or stolen to be used in ships so that a few more of Halrloprillalar's race may escape?"

Louis's laugh was bitter. "How does this sound? They left a few jets in place. Then came a plague that killed off most of their machinery. Some of them panicked. They took all the ships they had, and they built more ships in a hurry and dismounted most of the att.i.tude jets to do it. They're still at it. They're leaving the Ringworld to its fate."

Chmeee said, "Fools. They did it to themselves."

"Did they? I wonder."

"But this is just the possibility I find ominous," said the puppeteer. "Would they not have taken as much of their civilization as they could move? Certainly they would have taken trans.m.u.tation machinery."

Oddly, Louis was not even tempted to laugh. But what answer could he make?

The kzin found an answer. "They would take all they could reach. Anything near the s.p.a.ceport ledges. Anything near the rim wall, where the rim transport system was available. We must search inward, and we must search out the Repair Center. Any of Prill's people found there would have been trying to save the Ringworld, not leave it."

"Perhaps."

Louis said, "It would help if we knew just when the plague started eating their superconductors."

If he thought the Hindmost would flinch, he was wrong. The puppeteer said, "You will likely learn that before I do."

"I think you know already."

"Call me if you learn anything." The snaky heads disappeared.

Chmeee was looking at him strangely, but he said nothing. Louis returned to the flight controls.

The terminator line was a vast shadow encroaching from spinward when Chmeee spotted the city. They had followed a sand-filled riverbed to port of the dry sea. The river forked here, and the city nestled in the fork.

Prill's people had built tall, even where there was no obvious need. The city had not been wide, but it had been tall, until floating buildings smashed down into the lesser structures below. One slender tower still stood, but at a slant. It had driven itself like a spear into the lower levels. A road ran from port, along the outer edge of one branch of the dry river, then across a bridge so ma.s.sively braced that it had to belong to the Machine People. Halrloprillalar's people would have used stronger materials or would have floated it.

Chmeee said, "The city will have been looted."

"Well, yes, given that someone built a road to do the looting. Why don't you take us down anyway?"

"Your monkey curiosity?"

"Maybe. Just circle the tanj thing, give us a closer look."

Chmeee dropped the lander fast enough to put them in free fall. The kzin's fur was almost all grown out, a glossy and handsome orange coat, and a reminder of Chmeee's new youth. Adolescence wasn't helping his temper. Four Man-Kzin wars, plus a few "incidents" ... Louis kept his mouth shut.

The lander surged under them. Louis waited until the savage weight left him, then began adjusting the views through the outside cameras. He saw it almost instantly.

A boxlike vehicle was parked beside the tilted tower. It could have held up to a dozen pa.s.sengers. The motor housing at its rear should have been enough to lift a s.p.a.cecraft ... but this was a primitive people. He couldn't guess what they'd be using to move the vehicle. He pointed and said, "We find an isolated vehicle and swoop down on it, right?"

"Right." Chmeee let the lander settle. As he did, Louis studied the situation: The tower had speared down into a squarish building; had smashed through the roof and three stories and possibly into a bas.e.m.e.nt. It was the sh.e.l.l of the lesser building that held it upright. White puffs of steam or smoke jetted irregularly from two tower windows. Pale human shapes were dancing before the lower building's big front entrance-dancing, or holding sprinting contests-and two were resting p.r.o.ne, though in unrestful positions ...

Just before the single remaining wall of a collapsed building rose to block Louis's view, it all jumped into his mind's focus. The pale ones were trying to reach the entrance across a rubble-covered street. Someone in the tower was shooting at them.

The lander settled. Chmeee stood and stretched. "You seem to have your own luck, Louis. We can take the ones with the guns to be the Machine People. Our strategy will be to come to their aid."

It seemed reasonable. "Do you know anything about projectile weapons?"

"If we a.s.sume chemical propellants, a portable weapon will not penetrate impact armor. We can enter the tower via flying belts. Carry stunners. We would not want to kill our future allies."

They emerged into full night. Clouds had closed over the sky. Even so, Archlight glowed through in a faint broad band, and the floating city was a tight star-cl.u.s.ter to port. You couldn't get lost.

Louis Wu was not comfortable. The impact armor was too stiff; the hood covered most of his face. The padded straps of the flying belt constricted his breathing, and his feet dangled. But nothing was ever again going to feel like an hour under the wire, and that was that. At least he felt relatively safe.

He hung in the sky and used light-amplified binocular goggles.

The attackers didn't seem that formidable. They were quite naked and weaponless. Their hair was silver; their skin was very white. They were slender and pretty; even the men were more pretty than handsome, and beardless.

They kept to the shadows and the cover provided by fragments of broken buildings, except when one or two would sprint for the great doorway, zigzagging. Louis had counted twenty, eleven of them women. Five more were dead in the street. There might be others already in the building.

The defenders had stopped firing now. Perhaps they had run out of ammunition. They had been using two windows in the downward-slanting face of the tower, perhaps six stories up. Every window in the tower was broken.

He eased close to the larger floating shape of Chmeee. "We go in the other side, with lights at low intensity and wide aperture. I go first because I'm human. Right?"

"Right," said Chmeee.

The belts lifted by scrith repulsion, like the lander. There were small thrusters in back. Louis circled round, checked to see Chmeee following, and floated in one of the windows at what he hoped was the right level.

It was one big room, and it was empty. The smell made him want to sneeze. There was web furniture with the webbing rotted away, and a long gla.s.s table, shattered. At the bottom of the sloping floor, a shapeless thing proved to be a pack with shoulder straps. So: they had been here. And the smell- "Cordite," Chmeee said. "Chemical propulsives. If they shoot at us, cover your eyes." He moved toward a door. He flattened himself against the wall and flung the door suddenly open. A toilet, empty.

A bigger door hung open with the slant of the floor. With stunner in one hand and flashlight-laser in the other, Louis moved toward it. He felt a driving excitement drowning the fear.

Beyond the ornately carved wooden door, a broad circular staircase wound down into darkness. Louis shined his light down along loops of railing to where the spiral of stairs and the bottom of the building all crumpled in on itself. The light picked out a two-handed weapon with a shoulder b.u.t.t, and a box that had spilled tiny golden cylinders; another weapon further down; a coat equipped with straps; more sc.r.a.ps of clothing on the lower stair; a human shape crumpled in the crushed bottom of the stairway-a naked man, seeming darker and more muscular than the attackers.

Louis's excitement was growing unbearable. Was this really what he had needed all along? Not the droud and wire, but the risk of his life to prove its value! Louis adjusted his flying belt and dropped over the railing.