Needle balanced on belly thrusters. .992 gravities of thrust warped its path into the Ringworld's curve; left to itself, the ship would have flung itself outward toward interstellar s.p.a.ce. Louis watched the puppeteer's heads darting and weaving to check the dials and meters and screens around him. Louis couldn't read them.

The dark line had become a row of rings set well apart, each ring a hundred miles across, drifting past. During the first expedition, an old recording had shown them how ships would position themselves fifty miles from the rim wall and wait for the rings to sweep them up and accelerate them from free fall to Ringworld rotational speed and then dump them at the far end, on the s.p.a.ceport ledge.

To left and right the black wall converged at vanishing points. It was close now, a few thousand miles away. The Hindmost tilted Needle to coast along the linear accelerator. Hundreds of thousands of miles of rings ... but the Ringworlders had lacked gravity generators. Their ships and crews would not tolerate high accelerations.

"The rings are inactive. I find not even sensors for incoming ships," a puppeteer head turned to tell them, and then turned quickly back to work.

Here came the s.p.a.ceport ledge.

It was seventy miles across. There were tall cranes built in beautiful curves, and rounded buildings, and low, wide flatbed trucks. There were ships: four flat-nosed cylinders, of which three had been damaged, the curve of the hulls broken.

"I hope you brought lights," Chmeee said.

"I do not want to be noticed yet."

"Do you find any sign of awareness? Will you land us without lights?"

"No and no," said the Hindmost. The spotlight flared from Needle's nose, tremendously powerful: an auxiliary weapon, of course.

The ships were vast. An open airlock was a mere black speck. Thousands of windows glittered on the cylinders precisely like candy flecks sprinkled on a cake. One ship seemed intact. The others had been torn open and cannibalized in varying degrees, their guts opened to vacuum and prying alien eyes.

"Nothing attacks, nothing warns us," the puppeteer said. "The temperature of the buildings and machinery is as that of the ledge and the ships, 174 (one hundred seventy-four degrees) Absolute. This place is long abandoned."

A pair of ma.s.sive toroids, copper-colored, ringed the waist of the intact ship. They must have been a third the ma.s.s of the ship itself, or more. Louis pointed them out. "Ramscoop generators, maybe. I studied the history of s.p.a.ceflight once. A Bussard ramjet generates an electromagnetic field to scoop up interstellar hydrogen and guide it into a constriction zone for fusion. Infinite fuel supply. But you need an inboard tank and rocket motor for when you're moving too slow for the ramscoop. There." Tanks were visible within two of the rifled ships.

And on all three of the rifled ships, the ma.s.sive toroids were missing. That puzzled Louis. But Bussard ramjets commonly used magnetic monopoles, and monopoles could be valuable in other contexts.

Something else was bothering the Hindmost.

"Tanks to carry the lead? But why not simply plate it around the ship, where it would serve as shielding before it need be trans.m.u.ted into fuel?"

Louis was silent. There had been no lead.

"Availability," Chmeee said. "Perhaps they had to fight battles. Lead could be boiled from the hull, leaving the ship without fuel. Land us, Hindmost, and we will seek answers in the unharmed ship."

Needle hovered.

"Easy to depart," Chmeee insinuated. "Ease us off the ledge and turn off the thrusters. We fall to flat s.p.a.ce, activate the hyperdrive and rush for safety."

Needle settled on the s.p.a.ceport ledge. The Hindmost said, "Take your place on the stepping discs."

Chmeee did. He was ... not chuckling, but purring as he vanished. Louis stepped after him and was elsewhere.

Chapter 6 -.

"Now Here's My Plan ..."

The room felt familiar. He'd never seen one exactly like it, but it looked like the flight deck on any small interplanetary s.p.a.cecraft. You always needed cabin gravity, a ship's computer, thrust controls, att.i.tude jets, a ma.s.s detector. The three control chairs were recliners equipped with crash webs, controls in the arms, urinal tubes, and slots for food and drink. One chair was much larger than the others, that was all. Louis felt he could fly the lander blindfolded.

There was a broad strip of wraparound window above a semicircle of screens and dials. Through the window Louis watched a section of Needle's hull swing out and up. The hanger was open to s.p.a.ce.

Chmeee glanced over the larger k.n.o.bs and switches set before his own chair. "We have weapons," he said softly.

A screen blinked and showed a foreshortened puppeteer head, which said, "Descend the steps to reach your vacuum equipment."

The lander's stairs were broad and shallow, made for a kzin's tread. Below was a much larger area, living s.p.a.ce, with a water bed and sleeping plates and a kitchen the duplicate of the one in their cell. There was an autodoc big enough for a kzin, with an elaborate control console. Louis had been an experimental surgeon once. Perhaps the Hindmost knew it.

Chmeee had found the vacuum equipment behind one of an array of locker doors. He encased himself in what looked like an a.s.sortment of transparent balloons. He was edgy with impatience. "Louis! Gear yourself!"

Louis pulled on a flexible one-piece suit, skintight, and attached the fishbowl helmet and backpack. It was standard equipment; the suit would pa.s.s sweat, letting the body be its own cooling system. Louis added a loose oversuit lined in silver. It would be cold out there.

The airlock was built for three. Good: Louis could picture times when he wouldn't want to wait outside while an airlock cycled for someone else. If the Hindmost wasn't expecting emergencies, he had prepared for them anyway. As air was replaced by vacuum, Louis's chest expanded. He pulled shut the "girdle," the wide elastic band around his middle that would help him exhale.

Chmeee strode out of the lander, out of Needle, into the night. Louis picked up a tool kit and followed at an easy jog.

The sense of freedom was heady, dangerous. Louis reminded himself that his suit's communication link included the Hindmost. Things had to be said, and soon, but not in the puppeteer's hearing.

Proportions were wrong here. The half-disa.s.sembled ships were too big. The horizon was too close and too sharp. An infinite black wall cut the brilliant, half-familiar starscape in half. Seen through vacuum, the shapes of distant objects remained sharp and clear up to hundreds of thousands of miles away.

The nearest Ringworld ship, the intact one, looked to be half a mile distant. It was more like a mile. On the last voyage he had constantly misjudged the scale of things, and twenty-three years hadn't cured him.

He arrived puffing beneath the huge ship, to find an escalator built into one landing leg. The ancient machinery wasn't working, of course. He trudged up.

Chmeee was trying to work the controls of a big airlock. He fished a grippy out of the kit Louis carried. "Best not to burn through doors yet," he said. "There is power." He pried a cover off and worked at the innards.

The outer door closed. The inner door opened on vacuum and darkness. Chmeee turned on his flashlight-laser.

Louis was a little daunted. This ship would probably carry enough people to fill a small town. Easy to get lost here. "We want inspection tubes," he said. "I'd like to get the ship pressurized. With that big helmet you couldn't get into an access tube built for men."

They turned into a corridor that curved with the curve of the hull. There were doors just taller than Louis's head. Louis opened some of the doors. He found small living cubicles with bunks and pull-down chairs for humanoids his own size and smaller.

"I'd say Halrloprillalar's people built these ships."

Chmeee said, "We knew that. Her people built the Ringworld."

"That they did not do," said Louis. "I wondered if they built the ships or took them over from someone else."

The Hindmost spoke in their helmets. "Louis? Halrloprillalar told you her people built the Ringworld. Do you think she lied?"

"Yes."

"Why?"

She'd lied about other things. Louis didn't say so. He said, "Style. We know they built the cities. All those floating buildings, they're the kind of thing you put up to show off your wealth and power. Remember the sky castle, the floating building with the map room in it? Nessus took back tapes."

"I studied them," said the puppeteer.

"And it had a raised throne and a wire sculpture of someone's head that was as big as a house! If you could build a Ringworld, would you bother with a sky castle? I don't believe it. I never believed it."

"Chmeee?"

The kzin said, "We must accept Louis's judgment on human matters."

They turned right into a radial corridor. Here were more sleeping rooms. Louis inspected one in detail. The pressure suit was interesting. It was mounted against a wall like a hunter's trophy hide: one piece, crisscrossed with zippers, all open. Instantly accessible in case of vacuum.

The kzin waited impatiently while Louis zipped it shut and stepped back to study the effect.

The joints bulged. Knees and shoulders and elbows like cantaloupes, hands like a fistful of walnuts strung together. The face jutted forward; there were power and air-reserve gauges set below the faceplate.

The kzin growled, "Well?"

"Nope, I need more proof. Let's go."

"More proof of what?"

I think I know who built the Ringworld ... and why the natives are so much like humans. But why would they build something they couldn't defend? It doesn't make sense."

"If we discussed it-"

"Nope, not yet. Come on."

At the ship's axis they found pay dirt. Half a dozen radial corridors converged, and a tube with a ladder led up and down. There were diagrams covering four sections of wall, with labels that were tiny, detailed pictograms.

"How convenient," said Louis. "It's almost as if they had us in mind."

"Languages change," said the kzin. "These people rode the winds of relativity; their crews might be born a century apart. They would have needed such aids. We held our empire together with similar aids, before the Wars With Men. Louis, I find no weaponry section."

"There was nothing guarding the s.p.a.ceport either. Nothing obvious, anyway." Louis's finger traced the diagrams. "Galley, hospital, living area-we're here in the living area. Three control centers; seems excessive."

"One for the Bussard ramjet and interstellar s.p.a.ce. One for fusion drive and maneuvering in an occupied system, and weapons control, if any. One for life support: this one, that shows wind blowing through a corridor."

The Hindmost spoke. "With trans.m.u.tation, they would use a total conversion drive."

"Oh, not necessarily. A blast of radiation that powerful would play merry h.e.l.l in an inhabited system," said Louis. "Hah! There are our access tubes, going to ... ramscoop generators, fusion motor, fuel feed. We want the life-support controls first. Two flights up and that way."

The control room was small: a padded bench facing three walls of dials and switches. A touchpoint in the doorjamb caused the walls to glow yellow-white, and set the dials glowing too. They were unreadable, of course. Pictograms segregated the controls into cl.u.s.ters governing entertainment, spin, water, sewage, food, air.

Louis began flipping switches. The ones most often used would be large and easy to reach. He stopped when he heard a whistling sound.

The pressure dial at his chin rose gradually.

There was low pressure at 40 percent oxygen. Humidity was low but not absent. No detectable noxious substances.

Chmeee had deflated his suit and was stripping it off. Louis removed his helmet, dropped the backpack, and peeled his suit away, all in unseemly haste. The air was dry and faintly stale.

Chmeee said, "I think we may start with the access tube to the fuel feed. Shall I lead?"

"Fine." Louis heard in his voice the tension and eagerness he'd tried to repress. With luck the Hindmost would miss it. Soon, now. He followed the kzin's orange back.

Out the door, turn right into a radius, follow to the ship's axis and down a ladder, and a great furry hand engulfed Louis's upper arm and pulled him into a corridor.

"We must talk," the kzin rumbled.

"Yeah, and about time too! If he can hear us now, we might as well give up. Listen-"

"The Hindmost will not hear us. Louis, we must capture Hot Needle of Inquiry. Have you given thought to this?"

"I have. It can't be done. You made a nice try, but what the futz were you going to do next? You can't fly Needle. You saw the controls."

"I can make the Hindmost fly it."

Louis shook his head. "Even if you could stand guard over him for two years, I think the life-support system would break down, trying to keep you both alive that long. That's the way he planned it."

"You would surrender?"

Louis sighed. "All right, let's look at it in detail. We can offer the Hindmost a credible bribe or a credible threat, or we can kill him if we think we can fly Needle afterward."

"Yes."

"We can't bribe him with a magic trans.m.u.tation device. There isn't any."

"I dreaded that you would blurt out the truth."

"No way. Once he knows we aren't needed, we're dead. And we don't have any other bribes." Louis continued, "We can't get to the flight deck. There may be stepping discs that would take us there, somewhere aboard Needle, but where are they and how do we get the Hindmost to turn them on? We can't attack him either. Projectiles won't go through a GP hull. There's flare shielding on the hull, and probably more flare shielding between our cell and the flight deck. A puppeteer wouldn't have ignored that. So we can't fire a laser at him because the walls would turn mirror-colored and bounce the beam back at us. What's left? Sonics? He just turns off the microphones. Have I left anything out?"

"Antimatter. You need not remind me that we have none."

"So we can't threaten him, we can't hurt him, and we can't reach the flight deck anyway."

The kzin clawed thoughtfully at the ruff around his neck.

"It just occurred to me," Louis said. "Maybe Needle can't get back to known s.p.a.ce at all."

"I don't see what you mean."

"We know too much. We're very bad publicity for the puppeteers. Odds are the Hindmost never planned to take us home. Well, why would he go himself? The place he wants to reach is the Fleet of Worlds, which is twenty or thirty light-years from here by now, in the opposite direction. Even if we could fly Needle, we probably don't have the life support to reach known s.p.a.ce."

"Shall we steal a Ringworld ship, then? This one?"

Louis shook his head. "We can look it over. But even if it's in good shape, we probably can't fly it. Halrloprillalar's people took crews of a thousand, and they never went that far, according to Prill ... though the Ringworld engineers probably did."

The kzin stood peculiarly still, as if afraid to release the energy bottled inside him. Louis began to realize how angry Chmeee was. "Do you counsel me to surrender, then? Is there not even vengeance for us?"