The Ringworld Engineers

by Larry Niven

  Chmeee had grown delirious. Louis made Harkabeeparolyn wear Chmeee’s impact armor. Teela had torn it open in the fight, but it was better than skin for a woman who planned to lie next to a delirious kzin.

  The armor probably saved her life at least once, when Chmeee slashed at her because she looked too much like Teela. She tended the kzin as best she could, feeding him water and nutrient from her pressure-suit helmet. By the fourth day Chmeee was rational, but still weak ... and ravenous. The syrup in a human’s pressure suit wasn’t enough.

  It took them four days in all to reach the approximate position of Needle, and another day cutting through walls until they found a solid block of fused basalt.

  A week after it had solidified, the rock was still warm. Louis left his floating disc and passengers far down the tunnel down which Teela had towed Needle. He had his pressure-suit helmet on, with clean air blowing into it, when he held the disintegrator two-handed and pressed the trigger.

  A hurricane of dust blew back at him. A tunnel formed ahead of him, and he walked into it.

  There was nothing to see, and no sound but the howl of basalt disintegrating and blowing past him, and lightning somewhere behind him where the electron charges were reasserting their prerogatives. Just how much lava had Teela poured? It seemed he’d been at this for hours.

  He bumped into something.

  Yeah. He was looking through a window into a strange place. A living room, with couches and a floating coffee table. But everything looked soft, somehow; there wasn’t a sharp edge or a hard surface anywhere—nothing that any living thing could bump a knee against. Through a further window he could see huge buildings, and a glimpse of black sky between. Pierson’s puppeteers swarmed in the streets. Everything was upside down.

  That which he had taken for one of the couches wasn’t. Louis used his flashlight-laser at low intensity. He flicked it on and off. For a good minute nothing happened. Then a flattish white head and neck, emerging to drink from a shallow bowl, jerked in amazement and darted back under its belly.

  Louis waited.

  The puppeteer stood up. He led Louis around the hull—slowly, because Louis had to make his path with the disintegrator—to where he had placed a stepping-disc transmitter on the outside of the hull. Louis nodded. He went back for his companions.

  Ten minutes later he was inside. Eleven minutes later, he and Harkabeeparolyn were eating like kzinti. Chmeee’s hunger was beyond description. Kawaresksenjajok watched him in awe. Harkabeeparolyn hadn’t even noticed.

  Ship’s morning, for a spacecraft buried in congealed lava, tens of miles beneath the sunlight.

  “Our medical facilities are crippled,” the Hindmost said. “Chmeee and Harkabeeparolyn must heal as best they can.”

  He was on the flight deck, speaking via the intercom system; and that might or might-not have been significant. Teela was gone, and the Ringworld might survive. The puppeteer suddenly had a long, long life span to protect. Rubbing shoulders with aliens was contraindicated.

  “I have lost contact with both the lander and the probe,” the puppeteer said. “The meteor defense flared at about the time the lander stopped sending, for whatever significance that may have. Signals from the damaged probe stopped just after Teela Brown tried to invade Needle.”

  Chmeee had slept (on the water bed, quite alone) and eaten. His restored pelt would bear interesting scars once again, but the wounds were healing. He said, “Teela must have destroyed the probe as soon as she saw it. She could not force herself to leave a dangerous enemy behind her.”

  “Behind her? Who?”

  “Hindmost, she called you more dangerous than a kzin. A tactical ploy, to insult us both, no doubt.”

  “Did she indeed.” Two flat heads looked into each other’s eyes for a moment. “Well. Our resources have dwindled to Needle itself and a single probe. We left that probe on a peak near the floating city. It still has working sensors, and I have signaled it to return, in case we think of a use for it. We should have it available in six local days.

  “Meanwhile we seem to have our original problem back, with additional clues and additional complications. How to restore the Ringworld’s stability? We believe that we are in the right place to begin,” the Hindmost said. “Don’t we? Teela’s behavior, inconsistent for a being of acknowledged intelligence ...”

  Louis Wu made no comment. Louis was quiet this morning.

  Kawaresksenjajok and Harkabeeparolyn sat cross-legged against a wall, close enough that their arms were touching. Harkabeeparolyn’s arm was padded and in a sling. From time to time the boy glanced at her. She puzzled and worried him. She was running on painkillers, of course, but that wasn’t enough to account for her torpor. Louis knew he ought to talk to the boy ... if he knew what to say.

  The City Builders had slept in the cargo hold. Fear of falling would have kept Harkabeeparolyn out of the sleeping field in any case. She had offered rishathra, without urgency, when Louis joined them for breakfast. “But be careful of my arm, Luweewu.”

  Refusing sex took tact in Louis’s culture. He had told her that he was afraid of jarring her arm, which he was. It was equally true that he couldn’t seem to work up an interest. He wondered if tree-of-life had affected him so. But he sensed no lust in himself for yellow roots, nor even for a wire trickling electric current.

  This morning he seemed to have no strong urges at all.

  Fifteen hundred billion people ...

  The Hindmost said, “Let us accept Louis’s judgment regarding Teela Brown. Teela brought us here. Her intent matched our own. She gave us as many clues as she could. But what clues? She was fighting both sides of a battle. Was it important for her to create three more protectors, then kill two of them? Louis?”

  Louis, lost in thought, felt four sharp points prick his skin above the carotid artery. He said, “Sorry?”

  The Hindmost started to repeat himself. Louis shook his head violently. “She killed them with the meteor defense. She fired the meteor defense, twice, at targets other than our vitally necessary selves. We were allowed to watch it without being in stasis at the time. Just another message.”

  Chmeee asked, “Do you assume that she could have chosen other weapons?”

  “Weapons, times, circumstances, number of operating protectors—she had considerable choice.”

  “Are you playing games with us now, Louis? If you know something, why not tell us?”

  Louis’s guilty glance at the City Builders showed Harkabeeparolyn trying to stay awake, Kawaresksenjajok listening intently. A pair of self-elected heroes waiting their chance to help save the world. Tanj. He said, “One point five trillion people.”

  “To save twenty-eight point five trillion, and ourselves.”

  “You didn’t get to know them, Chmeee. Not as many, anyway. I was hoping one of you would think of this. I’ve been thrashing around in my head trying to see some—“

  “Know them? Know who?”

  “Valavirgillin. Ginjerofer. The king giant. Mar Korssil. Laliskareerlyar and Fortaralisplyar. Herders, Grass Giants, Amphibians, Hanging People, Night People, Night Hunters ... We’re supposed to kill 5 percent to save 95 percent. Don’t those numbers sound familiar to you?”

  It was the puppeteer who answered. “The Ringworld’s attitude jet system is 5 percent functional. Teela’s repair crew remounted them over 5 percent of the arc of the Ringworld. Are these the people who must die, Louis? The people on that arc?”

  Harkabeeparolyn and Kawaresksenjajok stared in disbelief. Louis spread his arms, helpless. “I’m sorry.”

  The boy cried, “Luweewu! Why?”

  “I promised,” said Louis. “If I hadn’t promised maybe I’d have a decision to make. I told Valavirgillin I’d save the Ringworld no matter w
hat it took. I promised I’d save her, too, if I could, but I can’t. We don’t have time to find her. The longer we wait, the bigger the force pushing the Ringworld off center. So she’s on the arc. So’s the floating city, and the Machine People empire, and the little red carnivores and the Grass Giants. So they die.”

  Harkabeeparolyn beat the heels of her hands together. “But this is everyone we know in the world, even by reputation!”

  “Me too.”

  “But this leaves nothing worth saving! Why must they die? How?”

  “Dead is dead,” said Louis. Then, “Radiation poisoning. Fifteen hundred billion people of twenty or thirty species. But only if we do everything exactly right. First we have to find out where we are.”

  The Puppeteer asked reasonably, “Where do we need to be?”

  “Two places. Places that control the meteor defense. We have to be able to guide the plasma jets, the solar flares. And we have to disconnect the subsystem that causes the plasma jet to lase.”

  “I have already found these places,” the Hindmost said. “While you were gone, the meteor defense fired, possibly to destroy the lander. Magnetic effects scrambled half my sensor equipment. Nonetheless I traced the origin of the impulse. The massive currents in the Ringworld floor that make and manipulate solar flares derive from a point beneath the north pole of the Map of Mars.”

  Chmeee said, “Perhaps the equipment must be cooled—“

  “Futz that! What about the laser effect?”

  “Activity there came hours later: smaller electrical effects, patterned. I told you of this source. It is just over our heads, by ship’s orientation.”

  “I take it we must disconnect this system,” Chmeee said.

  Louis snorted. “It’s easy. I could do it with a flashlight-laser or a bomb or the disintegrator. Learning how to make solar flares will be the hard part. The controls probably weren’t designed for idiots, and we don’t have too much time.”

  “And afterward?”

  “Then we put a blowtorch against inhabited land.”

  “Louis! Details!”

  He would be speaking a death sentence for a score of species.

  Kawaresksenjajok wouldn’t show his face. Harkabeeparolyn’s face was set like stone. She said, “Do what you must.”

  He did. “The attitude jet system is only 5 percent operational.”

  Chmeee waited.

  “Operating fuel is hot protons streaming from the sun. The solar wind.”

  The puppeteer said, “Ah. We flare the sun to multiply the fuel intake by a factor of twenty. Life forms beneath the flare die or mutate drastically. Thrust increases by the same factor. The attitude jets either take us to safety or explode.”

  “We don’t really have time to redesign them, Hindmost.”

  Chmeee said, “Irrelevant unless Louis is totally wrong. Teela inspected those motors while mounting them.”

  “Yeah. If they weren’t strong enough, she talked herself into adding an overdesign safety factor. Guarding against the mischance of a large solar flare. She knew that was possible. Doublethink!”

  “To guide the flare is not necessary to us, merely convenient,” the kzin continued. “Let the laser-generating subsystem be disconnected. Then, if need be, Needle may be placed where we want the flare to fall, then used as a target: accelerated until the meteor defense fires. Needle is invulnerable.”

  Louis nodded. “We’d like something a little more accurate. We’d do the job faster and kill less people. But ... yeah. We can do it all. We can do it.”

  The Hindmost came with them to inspect the components of the meteor defense. Nobody talked him into that. The sensor devices they dismounted from Needle had to be operated by a puppeteer’s lips and tongue. When he suggested teaching Louis how to manipulate the controls using a pick and tweezers, Louis laughed at him.

  The Hindmost spent some hours in the blocked section of Needle. Then he followed them out through the tunnel. His mane was dyed in streaks of a hundred glowing colors, and beautifully groomed. Louis thought, Everyone wants to look good at his own funeral, and wondered if that was it.

  It wasn’t necessary to use a bomb on the laser subsystem. Finding the off switch took the Hindmost a full day and a disc-load of the dismounted instruments, but it was there.

  The web of superconductor cables had its nexus in the scrith twenty miles beneath the north pole of the Map of Mars. They found a central pillar twenty miles tall, a sheath of scrith enclosing the cooling pumps for the Map of Mars. The complex at the bottom must be the control center, they decided. They found a maze of huge airlocks, and each had to be passed by solving some kind of design puzzle. The Hindmost handled that.

  They passed through the last door. Beyond was a brightly lighted dome, and dry-looking soil with a podium in the center, and a smell that sent Louis spinning around, running for his life, towing a bewildered Kawaresksenjajok by his thin wrist. The airlock was closed before the boy started to fight. Louis batted him across the head and kept going. They had passed through three airlocks before he let them stop.

  Presently Chmeee joined them. “The path led across a patch of soil beneath artificial sunlights. The automated gardening equipment has failed, and few plants still grow, but I recognized them.”

  “So did I,” said Louis.

  “I knew the smell. Mildly unpleasant.”

  The boy was crying. “I didn’t smell anything! Why did you throw me around like that? Why did you hit me?”

  “Flup,” said Louis. It had finally occurred to him that Kawaresksenjajok was too young; the smell of tree-of-life wouldn’t mean anything to him.

  So the City Builder boy stayed with the aliens. But Louis Wu didn’t see what went on in the control room. He returned to Needle alone.

  The probe was still far around the Ringworld, light-minutes distant. A hologram window, glowing within the black basalt outside Needle’s wall, looked out through the probe’s camera: a dimmed telescopic view of a sun somewhat less active than Sol. The Hindmost must have set that up before he left.

  The bone in Harkabeeparolyn’s arm was healing slightly crooked; Teela’s old portable ‘doc couldn’t set it. But it was healing. Louis worried more about her emotional state.

  With nothing of her own world around her, and flame about to take everything she remembered—call it culture shock. He found her on the water bed watching the magnified sun. She nodded when he greeted her. Hours later she hadn’t moved.

  Louis tried to get her talking. It wasn’t good. She was trying to forget her past, all of it.

  He found a better approach when he tried to explain the physical situation. She knew some physics. He didn’t have access to Needle’s computer and hologram facilities, so he drew diagrams on the walls. He waved his arms a lot. She seemed to understand.

  On the second night after his return, he woke to see her cross-legged on the water bed, watching him thoughtfully, holding the flashlight-laser in her lap. He met its glassy stare, then swung his arm in circles to turn himself over and went back to sleep. He woke up next morning, so what the tanj.

  That afternoon he and Harkabeeparolyn watched a flame rise from the sun, licking out and out and out. They said very little.

  EPILOGUE

  One falan later: ten Ringworld rotations.

  Far up the arc of the Ringworld, twenty-one candle flames glowed brightly, as brightly as the corona of the hyperactive sun showing around the edges of a shadow square.

  Needle was still embedded in basalt beneath the Map of Mars. Needles crew watched in a hologram window, courtesy of the probe’s cameras. The probe had been brought to rest at the cliff edge of the Map of Mars, on carbon dioxide snow, where martians were not likely to tamper with it.

/>   Between those two rows of candle flames, plants and animals and people would be dying. In numbers that would make human space look empty, the plants would be withering or growing strangely. Insects and animals would breed, but not according to their kind. Valavirgillin would be wondering why her father had died and why she was throwing up so often and whether it was part of the general doom and what was the Star People man doing about it all?

  But none of that showed from fifty-seven million miles away. They saw only the flames of the Bussard ramjets burning enriched fuel.

  “I am pleased to announce,” the Hindmost said, “that the center of mass of the Ringworld is moving back toward the sun. In another six or seven rotations we can set the meteor defense as we found it, to fire on meteors. Five percent of attitude jet efficiency will be enough to hold the structure in place.”

  Chmeee grunted in satisfaction. Louis and the City Builders continued to awe into the hologram glowing in a depth of black basalt.

  “We have won,” the Hindmost said. “Louis, you set me a task whose magnitude compares only to the building of the Ringworld itself, and you set my life at stake. I can accept your arrogance now that we have won, but there are limits. I will hear you congratulate me or I will cut off your air.”

  “Congratulations,” said Louis Wu.

  The woman and boy on either side of him began to cry.

  Chmeee snorted. “To the victor belongs the right to gloat, at minimum. Do the dead and dying bother you? Those worth your respect would have volunteered.”

  “I didn’t give them the chance. Look, I’m not asking you to be guilt-ridden—“

  “Why should I be? I mean no offense, but the dead and dying are all hominids. They are not of your species, Louis, and they are certainly not of mine, nor of the Hindmost’s. I am a hero. I have saved the equivalent of two inhabited worlds, and their populations are of my species, or nearly so.”