Protector

by Larry Niven

  They would try to break in. Intelligent beings were curious.

  Twing was tough, but not invulnerable.

  Phssthpok leapt straight upward, through the hatch and into the control cubby. He hated to leave the captive, but there was no choice. He closed the door to the cargo hold, tested it to be sure it was locked. He climbed rapidly into his pressure suit.

  Three measured thumps from somewhere below him. Pause.

  Something thumped next to his right arm. Phssthpok applied the softener key to the twing. Thump—and a foot of crude glass rod slammed through the twing. Phssthpok yanked hard on it, reached through the wall and had something softer. He pulled.

  He had something roughly Pak-shaped, both smaller and denser than a Pak. It was clutching a reversed spear. Phssthpok hit it savagely where its head joined its shoulders. Something broke, and it went limp. Phssthpok probed its body for soft spots. There was a spot in the middle of its body where bone did not protect. Phssthpok pushed hard into it and clutched with his fingers until he felt something give. Presumably it was dead.

  It began to smoke.

  Phssthpok watched.

  Something in the pod’s atmosphere was causing it to give off fumes. That seemed promising. The spear did not speak for a high civilization. Probably they would have nothing that could penetrate twing. He did not like to risk it—but the alternative was to leak his own breathing-air into the surrounding dust, to poison it.

  He opened his helmet for a moment and sniffed. Closed it fast. But he’d smelled chemicals he was familiar with…

  He got a squeeze of water, trickled it on the alien’s leg. The result was a fireball. Phssthpok leapt away. From across the room he watched the alien burn.

  That seemed straightforward enough.

  He went to work rigging a hose from the pod’s water supply to the hull. His last moves he made in haste: using the softener key, running the hose through the hull, removing the key to harden the twing, then running water. There was frantic thumping from all over the hull. It stopped rather suddenly.

  He ran most of his reserve of water out into the dust.

  He waited several hours, until the whine of the air system dropped to normal. Then he doffed his pressure suit and rejoined Brennan. The captive had noticed nothing.

  The water should hold off the natives for awhile. But Phssthpok’s reserves were dwindling almost ludicrously. His ship was abandoned, his remaining drive system was useless, his environment bordered by a spherical shell of dust. Now his water reserve was gone. His life story was almost visibly coming to a close.

  Presently he dreamed.

  The Blue Ox had circled the sun and was now on the other side of the system, headed for interstellar space. Between Ox and U Thant there was a communications gap of thirty minutes. Sohl and Garner waited, knowing that any information would be half-an-hour late.

  Mars was three-quarters fall and impressively large in their rear view camera.

  They had asked all the questions, made guesses at the answers, mapped out their search pattern of the Lacis Solis region. Luke was bored. He missed the conveniences built into his travel chair. He thought Nick was bored too, but he was wrong. In space Nick was silent by habit.

  The screen flashed on: a woman’s face. The radio cleared its throat and spoke.

  “U Thant, this is Tina Jordan aboard Blue Ox.” Luke sensed the woman’s barely repressed panic. Tina caught on her own voice, then blurted, “We’re in trouble. We were testing that alien root in the lab and Einar took a bite out of it! The damn thing was like asbestos from vacuum exposure, but he chewed a piece off and swallowed if before we could stop him. I can’t understand why he did it. It smelled awful!

  “Einar’s sick, very sick. He tried to kill me when I took the root away from him. Now he’s gone into coma. We’ve hooked him into the ship’s ’doc. The ’doc says Insufficient Data.” They heard a ragged intake of breath. Luke thought he could see bruises beginning to form on the woman’s throat. “We’d like permission to get him to a human doctor.”

  Nick cursed and keyed Transmit. “Nick Sohl speaking. Pick a route and get on it. Then finish analyzing that root. Did the smell remind you of anything? Sohl over.” He turned it off. “What the blazes got into him?”

  Luke shrugged. “He was hungry?”

  “Einar Nilsson, for Finagle’s sake! He was my boss for a year before he quit politics. Why would he try a suicidal trick like that? He’s not stupid.” Nick drummed on the arm of his chair, then began looking for Ceres with the com laser.

  In the half hour that passed before the Blue Ox called again, he got dossiers on all three of her crew. “Tina Jordan’s a flatlander. That explains why they waited for orders,” he said.

  “Does that need an explanation?”

  “Most Belters would have turned around the moment Einar came down sick. The Outsider ship’s empty, and there’s no problem tracking it. No real point in staying. But Jordan’s still a flatlander, still used to being told when to breathe, and La Pan probably didn’t trust his own judgment enough to override her.”

  “Age,” said Luke. “Nilsson was the oldest.”

  “What would that have to do with it?”

  “I don’t know. He was also the biggest. Maybe he was after a new taste thrill…no, dammit, I don’t believe it either—”

  “Blue Ox calling U Thant. We’re on our way home. Course plotted for Vesta. The root analyzes almost normal. High in carbohydrates, including right-hand sugars. The proteins look ordinary. No vitamins at all. We found two compounds Nate says are brand new. One resembles a hormone, testosterone, but it definitely isn’t testosterone.

  “The root doesn’t smell like anything I can name, except possibly sour milk or sour cream. The air in the Outsider ship was thin, with an adequate partial pressure of oxygen, no poisonous compounds, at least two percent helium. We spectroanalyzed the porthole material, and—” She listed a spectrum of elements, high in silicone. “The ’doc still reports Einar’s illness as Insufficient Data, but now there’s an emergency light. Whatever it is, it’s not good. Any further questions?”

  “Not at the moment,” said Nick. “Don’t call back, because we’re going to be too busy landing.” He signed off. He sat drumming on the console with long, tapering fingers. “Helium. That ought to tell us something.”

  “A small world with no moon,” Luke speculated. “Big moons tend to skim away a planet’s atmosphere. The Earth would look like Venus without her oversized moon. The helium would be the first to go, wouldn’t it?”

  “Maybe. It would also be the first to leave a small planet. Think about the Outsider’s strength. It was no small planet be came from.”

  Nick and Luke were men who would stop to think before speaking. Conversation aboard U Thant would lapse for minutes, then take up just where it had left off.

  “What then?”

  “From somewhere in a gas cloud, with lots of helium. The galactic core is in the direction he came from. Plenty of gas clouds and dust clouds in that direction.”

  “But that’s an unholy distance away. Will you stop that drumming?”

  “It helps me think. Like your smoking.”

  “Drum then.”

  “There’s no limit to how far he could have come. The faster a Bussard ramjet ship moves, the more fuel it would pick up.”

  “There has to be a limit at which the exhaust velocity equals the velocity at which the gas hits the ramscoop field.”

  “Possible. But it must be way the Finagle up there. That air tank was huge. The Outsider is a long way from home.”

  The autodoc was built into the back wall, set over one of the three disaster couches. Einar was in that couch. His arm was in the ’doc almost to the shoulder.

  Tina watched his face. He had been getting progressively worse. It did not look like sickness; it looked like age. Einar had aged decades in the past hour. He urgently needed a human doctor…but a higher thrust than the Ox’s would have killed him, and t
he Ox was all they had.

  Could they have stopped him? If she’d yelled at once—but then Einar had his hands on her throat, and it was too late. Where had Einar got such strength? He would have killed her.

  His chest stopped moving.

  Tina looked up at the dial faces on the ’doc. Usually a panel covered those dials; a spaceship has enough gadgets to watch without added distractions. Tina had been looking at those dials every five minutes, for hours. This time they all showed red.

  “He’s dead,” she said. She heard the surprise in her voice, and wondered at it. The cabin walls began to blur and recede.

  Nate squirmed out of the control couch and bent over Einar. “And you just noticed! He must have been dead for an hour!”

  “No, I swear…” Tina gulped against the rising anaesthesia in her veins. Her body was water. She was going to faint.

  “Look at his face and tell me that!”

  Tina climbed onto watery legs. She looked down at the ravaged face. Einar, dead, looked hundreds of years old. In sorrow and guilt and repugnance, she reached to touch the dead cheek.

  “He’s still warm.”

  “Warm?” Nate touched the corpse. “He’s on fire. Fever. Must have been alive seconds ago. Sorry, Tina, I jumped at conclusions. Hey! Are you all right?”

  “How dangerous are these approaches?”

  “Get that brave little quiver out of your voice,” said Nick. It was pure slander; Luke was nothing but interested. “I’ve made a couple of hundred of these in my life. For sheer thrills I’ve never found anything to beat letting you fly me to Death Valley Port.”

  “You said you were in a hurry.”

  “So I did. Luke, I’d like to request an admiring silence for the next few minutes.”

  “Aha! Ah HA!”

  The red planet reached for them, unfolding like a wargod’s fist. Nick’s bantering mood drained away. His face took on a set, stony look. He had not been quite candid with Luke. He had made several hundred powered approaches in his life; true. But those had been asteroid approaches, with gravity negligible or nearly so.

  Diemos went by in the direction technically known as “ship’s upward.” Nick inched a lever toward him. Mars was flattening out and simultaneously sliding away as they moved north.

  “The base should be there,” said Luke. “At the north edge of that arc. Ah, that must be it, that little crater.”

  “Use the scope.”

  “Mmmmm…dammit. Ah. There it is. Deflated, of course. See it, Nick?”

  “Yah.”

  It looked like the abandoned shred of a sky-blue toy balloon.

  Dust rose in churning clouds to meet their drive flame. Nick swore viciously and increased thrust. By now Luke had caught on to Nick’s vagaries in blasphemy. When he swore by Finagle it was for humor or emphasis. When he blasphemed in Christian fashion, he meant it.

  U Thant slowed and hovered. She was above the dust, then in the dust, and gradually the ochre clouds thinned and backed away. A ring shaped sandstorm receded toward three hundred and sixty degrees of horizon. The bedrock lay exposed for the first time in millennia. It was lumpy and brown and worn. In the light of the drive the rounded rock blazed white, with sharp black shadows. Where the drive flame touched it melted.

  Nick said, “I’ll have to land in the crater. That dust will flow back in as soon as I turn off the motor.” He angled the ship left and killed the drive. The bottom dropped out. They fell.

  They fell all the way on attitude jets, and touched with hardly a bounce.

  “Beautiful,” said Luke.

  “I do that all the time. I’m going to search the base. You monitor me on helmet camera.”

  The ring wall rose above him in worn, rounded, volcanic-looking stone. Dust dripped back from the rim, ran like molasses down the shallow slope to collect in a pool around the ship’s shock legs. The crater was half a mile across. In the approximate center was the dome, surrounded by a lapping sea of dust.

  Nick looked about him, frowning. There seemed no way to reach the dome without crossing the dust, which might not be as shallow as it looked. The crater was ancient; it looked just younger than the planet itself. But it was criss-crossed with younger cracks. Some of the edges were almost sharp; the air and dust were too thin to erode things quickly. There would be bad footing.

  He started around the base of the ring wall, walking with care. Dust concealed some of the cracks.

  A small, intense sun hung above the crater rim, in a deep purple sky.

  On the far side of the dome a narrow path of laser-fused dust led from the dome to the ring wall. It must have been made with the base’s communications laser. The boats were there, moored along the path. Nick did not pause to study them.

  There must have been dozens of slits in the dome material. Nick found twelve dried bodies within. Martians had murdered the base personnel over a century ago. They had killed Müller the same way, after Müller had re-inflated the dome.

  Nick searched each of the small buildings in turn. At some places he had to crawl beneath the transparent folds of the dome. There was no Outsider to meet him. There was no sign of tampering since Müller’s forced visit.

  “Dead end,” he reported. “Next step?”

  “You’ll have to carry me piggyback until we can find a sand boat.”

  Dust had settled over the boats, leaving only flat, wide shapes the color of everything else. For twelve years they had waited for another wave of explorers—explorers who had lost interest and gone home.

  It was like seeing ghosts. An Egyptian pharaoh might find such ghosts waiting for him in the afterworld: rank on rank of dumb, faithful retainers, gone before him, and waiting, waiting.

  “From here they look good,” said Luke. He settled himself more comfortably on Nick’s shoulders. “We’re in luck, Sinbad.”

  “Don’t count your money yet.” Nick started across the dust pond toward the dome. Luke was light on his shoulders, and his own body was light here; but together they were top-heavy. “If I start falling I’ll try to fall sideways. That dust won’t hurt either of us.”

  “Don’t fall.”

  “The UN fleet will probably be coming here too. To get the boats.”

  “They’re days behind us. Come on.”

  “The path’s slippery. Dust all over it.”

  The boats, three of them, were lined along the west side. Each had four seats and a pair of fans at the stern, below the dust line, caged for protection against submerged rocks. The boats were so flat that any ocean ripple would have sunk them; but in the heavy dust they rode high.

  Nick settled his burden not too gently into one of the seats. “See if she’ll start, Luke. I’m going to the dome for fuel.”

  “It’ll be hydrazine, with compressed martian air as oxidizer.”

  “I’ll just look for something labeled Fuel.”

  Luke was able to start the compressor, but the motor wouldn’t fire. Probably drained the tanks, he decided, and turned everything off. He found a bubble dome collapsed in the back. After making sure it was meant to be worked manually, he wrestled it into place and sealed it down, holding himself in place with a seat belt to get leverage. His long arms and wide hands had never lost an arm wrestling match. The edges of the bubble would probably leak, he decided, but not seriously. He found the inspection hatch that hid an air converter for changing the nitric oxides outside into breathable nitrogen and oxygen.

  Nick returned with a green tank balanced on one shoulder. He fueled the boat through an injector nozzle. Luke tried the starter again. It worked. The boat tried to take off without Nick. Luke found the neutral setting, then reverse. Nick waited while he backed up.

  “How do I get through the bubble?”

  “I guess you don’t.” Luke collapsed the bubble, unsealed one side for Nick, then sealed it after him. The bubble began to fill, slowly. “Best keep our suits on,” said Luke. “It may be an hour before we can breathe in here.”

  “You ca
n collapse it then. We’ve got to get provisions from the ship.”

  It was two hours before they raised the bubble and started for the opening in the ring wall.

  The dark sandstone cliffs that framed the opening were sharp and clear, clearly dynamite-blasted, as artificial as the glassy path between dome and ring wall. Nick was settled comfortably in one of the passenger chairs, his feet propped on another, his eyes on the screen of the dismounted deep-radar.

  “Seems deep enough now,” he said.

  “Then I’ll open her up,” said Luke. The fans spun; the stern dipped far down, then righted. They skimmed across the dust at ten knots, leaving two straight, shallow, regular swells as a wake.

  The deep-radar screen registered a density pattern in three dimensions. It showed a smooth bottom, regular swells and dips from which millions of years had eliminated all sharp lines and points. There was little volcanic activity on Mars.

  The desert was as flat as a mirror. Rounded dun rocks poked through its surface, incongruous, Daliesque. Craters sat on the dust like badly made clay ash trays. Some were a few inches across. Some were so large that they had to be seen from orbit. The horizon was straight and close and razor sharp, glowing yellow below and artery red above. Nick turned his head to watch the crater recede.

  His eyes widened, then squinted. Something?

  “Damn’t. Hold it!” he shouted. “Turn around! Turn hard left!”

  “Back toward the crater?”

  “Yes!”

  Luke cut the power in one motor. The boat turned its prow to the left but continued to skid sideways across the dust. Then the right fan bit in, and the boat curved around.

  “I see it,” said Luke.

  It was little more than a dot at that distance, but it showed clearly against the calm monochrome sea around it. And it moved. It jerked, it paused to rest, it jerked again, rolling sideways. It was several hundred yards from the crater wall.