by Larry Niven
“No.” Though Louis would have.
“I remember too little about Mars. The planet was never very important to your people, was it? It was no more than a source of legends. I do know that the Map is twenty miles high, to mimic the very rarefied air of the planet.”
“Twenty miles high, and fifty-six million square miles in area. That’s one billion, one hundred and twenty million cubic miles of hiding place.”
“Urrr,” said Chmeee. “You must be right. The Map of Mars is the Repair Center, and the Pak did their best to hide it. Chjarrl told me of the monsters and the storms and the distances of the Great Ocean. They would have made good passive guardians. A fleet of invaders might never have guessed the secret.”
Louis rubbed absently at four itching spots across his eyebrows. “One point twelve times ten to the ninth cubic miles. I have to admit it, that number leaves me numb. What were they keeping in there? Patches big enough to plug Fist-of-God Mountain? Machinery big enough to carry those patches, and plant them, and weld them tight? That winching equipment we saw on the rim wall, for the attitude jets? Spare attitude jets? Tanj, I’d love to find spare attitude jets. But they’d still have room to spare.”
“War fleets.”
“Yah. We already know about their big weapon, but—war fleets, of course, and ships to carry refugees, too. Maybe the whole Map is one big refugee ship. It must have been big enough to evacuate the Ringworld before the population started filling every niche in the ecology.”
“A spacecraft? Perhaps a spacecraft big enough to tow the Ringworld back into place? I have trouble thinking on this scale, Louis.”
“Me too. I don’t think it’d be big enough.”
“Then what did you have in mind when you destroyed our hyperdrive motor?” Suddenly the kzin was snarling.
Louis chose not to flinch. “I thought the Ringworld might be set up to act on the sun magnetically. I was almost right. The trouble—”
The Hindmost’s voice blared from a speaker. “Louis! Chmeee! Set the lander on autopilot and flick across to me now!”
Chapter 29
The Map of Mars
Chmeee reached the disc ahead of Louis, in one monstrous bound. The kzin could take orders too, Louis thought. He forbore to remark on the fact.
The City Builders were looking out through the hull, not at the passing seascape—which was nothing but blue sea and cloud-striped blue sky merging at the infinity-horizon—but at a movie-screen-sized hologram. As Chmeee appeared on the receiver disc they turned and flinched and then tried to hide it.
Louis said, “Chmeee, meet Harkabeeparolyn and Kawaresksenjajok, librarians from the floating city. They’ve been of great help in gaining us information.”
The kzin said, “Good. Hindmost, what is the problem?”
Louis tugged at the kzin’s fur and pointed.
“Yes,” said the puppeteer. “The sun.”
The sun showed dimmed and magnified in the hologram rectangle. A brilliant patch near the center was shifting, twisting, changing shape as they watched.
Chmeee said, “Wasn’t the sun doing that shortly before we boarded the spaceport ledge?”
“Right. You’re looking at the Ringworld meteor defense. Hindmost, what do we do now? We can slow down, but I don’t see any way to save the lander.”
“My first thought was to save your valuable selves,” the puppeteer said.
The sea threw back a highlight from directly below the fleeing Needle. Now it seemed to be growing brighter, with a violet tinge. Suddenly, momentarily, it was unbearably bright. Then it was a black spot on the hull beneath their feet.
And a thread of jet-black, outlined in violet-white, stood upon the spinward horizon. A vertical pillar, reaching from ground to sky. Above the atmosphere it was invisible.
The kzin spoke words in the Hero’s Tongue.
“All very well,” said the Hindmost in Interworld, “but what is it firing on? I assumed we were the target.”
Louis asked, “Isn’t the Map of Earth in that direction?”
“Yes. Also a good deal of water and considerable Ringworld landscape.”
Where the beam touched down, the horizon glowed white. Chmeee whispered in the Hero’s Tongue, but Louis caught the sense. “With such a weapon I could boil the Earth to vapor.”
“Shut up.”
“It was a natural thought, Louis.”
“Yah.”
The beam cut off abruptly. Then it touched down again, a few degrees to port.
“Tanj dammit! All right, Hindmost, take us up. Take us high enough to use the telescope.”
***
There was a glowing yellow-white point on the Map of Earth. It had the look of a major asteroid strike.
There was a similar glow farther away, at the far shore of the Great Ocean.
The solar flare had dimmed and was losing coherence.
Chmeee asked, “Were there aircraft or spacecraft in those directions? Fast-moving objects?”
“The instruments may have recorded something,” the Hindmost said.
“Find out. And take us down to one mile altitude. I think we want to approach the Map of Mars from below the surface.”
“Louis?”
“Do it.”
Chmeee asked, “Have you knowledge of how that laser beam was produced?”
“Louis can tell you,” the puppeteer said. “I will be busy.”
***
Needle and the lander converged on the Map of Mars from two directions. The Hindmost held the two vehicles parallel so that it was possible to cross between them.
Louis and Chmeee flicked across to the lander for lunch. Chmeee was hungry. He consumed several pounds of red meat, a salmon, a gallon of water. Louis’s own appetite suffered. He was pleased that his guests weren’t watching.
“I don’t understand why you picked up these passengers,” Chmeee said, “unless it was to mate with the woman. But why the boy?”
“They’re City Builders,” Louis said. “Their species ruled most of the Ringworld. And I plucked these two out of a library. Get to know them, Chmeee. Ask them questions.”
“They fear me.”
“You’re a soft-spoken diplomat, remember? I’m going to invite the boy to see the lander. Tell him stories. Tell him about Kzin and hunting parks and the House of the Patriarch’s Past. Tell him how kzinti mate.”
Louis flicked across to Needle, spoke to Kawaresksenjajok, and was back in the lander with him before Harkabeeparolyn quite realized what was happening.
Chmeee showed him how to fly. The lander swooped and did somersaults and darted skyward at his command. The boy was entranced. Chmeee showed him the magic of binocular goggles, and superconductor cloth, and impact armor.
The boy asked about kzinti mating practices.
Chmeee had mated with a female who could talk! It had opened new vistas for him. He told Kawaresksenjajok what he wanted to know—which Louis thought was pretty dull stuff—and then got the boy talking about mating and rishathra.
Kawaresksenjajok had no practice but a lot of theory. “We make records if a species will let us. We have archives of tapes. Some species have things they can do instead of rishathra, or they may like to watch or to talk about it. Some mate in only one position, others only in season, and this carries over. All of this influences trade relationships. There are aids of various kinds. Did Luweewu tell you about vampire perfume?”
They hardly noticed when Louis left to return to Needle alone.
Harkabeeparolyn was upset. “Luweewu, he might hurt Kawa!”
“They’re doing fine,” Louis told her. “Chmeee’s my crewmate, and he likes children of all species. He’s perfectly safe. If you want to be his friend too, scratch him behind the ears.”
“How did you hurt your forehead?”
“I was careless. Look, I know how to calm you down.”
They made love—well, rishathra–on the water bed, with the massage unit going. The woman might have hated Pant
h Building, but she had learned a good deal. Two hours later, when Louis was sure he would never move again, Harkabeeparolyn stroked his cheek and said, “My time of mating should end tomorrow. Then you may recover.”
“I have mixed feelings about that.” He chuckled.
“Luweewu, I would feel better if you would rejoin Chmeee and Kawa.”
“Okay. Behold as I stagger to my feet. See me at the stepping disc? There I go: poof, gone.”
“Luweewu—”
“Oh, all right.”
***
The Map of Mars was a dark line, growing, becoming a wall across their path. As Chmeee slowed, microphones on the lander’s hull picked up a steady whispering, louder than the wind of their passage.
They came to a wall of falling water.
From a mile distant it appeared perfectly straight and infinitely long. The top of the waterfall was twenty miles above their heads. The base was hidden in fog. Water thundered in their ears until Chmeee had to turn off the microphones, and then they could hear it through the hull.
“It’s like the water condensers in the city,” the boy said. “This must be where my people learned how to make water condensers. Chmeee, did I tell you about water condensers?”
“Yes. If the City Builders came this far, one wonders if they found the way inside. Do your tales tell anything of a hollow land?”
“No.”
Louis said, “Their magicians are all built like Pak protectors.”
The boy asked, “Luweewu, this great waterfall—why is there so much of it?”
“It must run all the way round the top of the Map. It takes out the water vapor. The top of the Map has to be kept dry,” Louis said. “Hindmost, are you listening?”
“Yes. Your orders?”
“We’ll circle with the lander, using deep-radar and the other instruments. Maybe we’ll find a door under the waterfall. We’ll use Needle to explore the top. How’s our fuel supply?”
“Adequate, given that we won’t be going home.”
“Good. We’ll dismount the probe and set it following Needle at … ten miles and ground-hugging altitude, I think. Keep the stepping-disc links and the microphones open. Chmeee, do you want to fly the lander?”
The kzin said, “Aye, aye.”
“Okay. Come on, Kawa.”
“I’d like to stay here,” the boy said.
“Harkabeeparolyn would kill me. Come on.”
***
Needle rose twenty miles, and red Mars stretched before them.
Kawaresksenjajok said, “It looks awful.”
Louis ignored that. “At least we know we’re looking for something big. Picture a blowout patch big enough to plug Fist-of-God Mountain. We want a hatch big enough for that patch plus the vehicle to lift it. Where would you put it on the Map of Mars? Hindmost?”
“Under the waterfall,” the Hindmost said. “Who would see? The ocean is empty. The failing water would hide all.”
“Yah. Makes sense. But Chmeee’s searching that. Where else?”
“I must hide the lines of a gigantic hatch in a martian landscape? Perhaps an irregular shape, with hinges in a long, straight canyon. Perhaps I would put it beneath the ice, melting and refreezing the north pole to conceal my comings and goings.”
“Is there a canyon like that?”
“Yes. I did my homework. Louis, the poles are the best gamble. Martians never went near the poles. Water killed them.”
The Map was a polar projection; the south pole was spread out around the rim. “Okay. Take us to the north pole. If we don’t find anything, we’ll spiral out from there. Stay high and keep all instruments going. We don’t care too much if something fires on Needle. Chmeee, are you listening?”
“I hear.”
“Tell us everything. Chances are you’ll find what were after. Don’t try to do anything about it.” Would he obey? “We don’t invade in the lander. We’re burglars. We’d rather be shot at in a General Products hull.”
***
Deep-radar stopped at the scrith floor. Above the scrith the mountains and valleys showed translucent. There were seas of marsdust fine enough to flow like oil. Under the dust were cities of a sort: stone buildings denser than the dust, with carved walls and rounded corners and a good many openings. The City Builders stared, and so did Louis Wu. Martians had been extinct in human space for hundreds of years.
The air was clear as vacuum. Off to starboard, well beyond the horizon, was a mountain taller than any on Earth. Mons Olympus, of course. And a splinter of white floated above the crater.
Needle fell, and pulled out of the fall just above the crescent dunes. The structure was still visible, floating fifty to sixty yards above the peak; and Needle must have been quite visible to its occupants.
“Chmeee?”
“Listening.”
Louis fought a tendency to whisper. “We’ve found a floating skyscraper. Maybe thirty stories tall, with bay windows and a landing ledge for cars. Built like a double cone. It looks very much like the building we took over on our first trip, the good ship Improbable.”
“Identical?”
“Not quite, but close. And it’s floating above the highest mountain on Mars, just like a god-tanjed signpost.”
“It does sound like a signal meant for us. Shall I flick through?”
“Not yet. Have you found anything?”
“I believe I’ve traced the lines of a tremendous hatch inside the waterfall. It would pass a war fleet or a patch to cover the crater in Fist-of-God. There may be signals to open it. I haven’t tried.”
“Don’t. Stand by. Hindmost?”
“I have radiation and deep-radar scans. The building is radiating little energy. Magnetic levitation does not require large amounts of power.”
“What’s inside?”
“Here.” The Hindmost gave them a view. By deep radar the structure showed translucent gray. It appeared to be a floating building modified for travel, with fuel tanks and an air-breathing motor built into the fifteenth floor. The puppeteer said, “Solid construction: walls of concrete or something equally dense. No vehicles in the carport. Those are telescopes or other sensor devices in the tower and the basement. I cannot tell if the structure is occupied.”
“That’s the problem, all right. I want to outline a strategy. You tell me how it sounds. One: we go as fast as possible to just above the peak.”
“Making perfect targets of ourselves.”
“We’re targets now.”
“Not from weapons inside Mons Olympus.”
“What the futz, we’re wearing a General Products hull. If nothing fires on us, we go to step two: we deep-radar the crater. It we find anything but a solid scrith floor we go to step three: vaporize that building. Can we do that? Fast?”
“Yes. We don’t have power storage to do it twice. What is step four?”
“Anything to get us inside quick. Chmeee stands by to rescue us any way he can. Now tell me whether you’re going to freeze up halfway through this procedure.”
“I wouldn’t dare.”
“Wait a bit.” It came to Louis that their native guests were scared spitless. To Harkabeeparolyn he said, “If there is a place in the world where the world can be saved, that place is below us. We think we’ve found the door. Someone else has found it too. We don’t know anything about him, or them. Understand?”
The woman said, “I’m frightened.”
“So am I. Can you keep the boy calm?”
“Can you keep me calm?” She laughed raggedly. “I’ll try.”
“Hindmost. Go.”
Needle leapt into the sky at twenty gravities, and rolled, and stopped upside down, almost alongside the floating building. Louis’s belly rolled too. Both City Builders shrieked. Kawaresksenjajok had a death grip on his arm.
Eyesight showed the crater plugged by old lava. Louis watched the deep-radar image.
It was there! A hole in the scrith, an inverted funnel leading up (down!) through the c
rater in Mons Olympus. It was far too small to pass Ringworld repair equipment. This was a mere escape hatch, but it was roomy enough for Needle.
“Fire,” Louis said.
The Hindmost had last used this beam as a spotlight. At close range it was devastating. The floating building became a streamer of incandescence with a cometlike head of boiling concrete. Then it was only dust cloud.
Louis said, “Dive.”
“Louis?”
“We’re a target here. We don’t have time. Dive. Twenty gravities. We’ll make our own door.”
The ocher landscape was a roof over their heads. Deep-radar showed a hole in the scrith, dropping to engulf them. But every other sense showed the solid lava crater in Mons Olympus descending at terrible speed to smash them.
Kawaresksenjajok’s nails in Louis’s arm were drawing blood. Harkabeeparolyn seemed frozen. Louis braced for the impact.
Darkness.
There was formless, milky light from the deep-radar screen. Something else was glowing somewhere: green and red and orange stars. Those were dials on the flight deck.
“Hindmost!”
No answer.
“Hindmost, give us some light! Use the spotlight! Let us see what’s threatening us!”
“What happened?” Harkabeeparolyn asked plaintively. Louis’s eyes were adjusting; he could see her sitting on the floor, hugging her knees.
Cabin lights came on. The Hindmost turned from the controls. He looked shrunken: half curled up already. “I can’t do this any more, Louis.”
“We can’t use the controls. You know that. Give us a spotlight so we can see out.”
The puppeteer touched controls. A white diffused light bathed the hull in front of the flight deck.
“We are embedded in something.” One head glanced down; the other said, “Lava. The outer hull is at seven hundred degrees. Lava was poured over us while we were in stasis and is now cooled.”
“Sounds like someone was ready for us. Are we still upside down?”
