Schild's Ladder

  Sophus shook his head. “She's been in transit almost a century, standard time.”

  That was a long journey. Though it cost you more lost years in total to travel by an indirect route, breaking up the trip with as many stops as possible eased the sense of alienation. Whatever faction she supported, she had to be serious about the cause.

  Tchicaya pictured a map of the region. “She's come from Chaitin?”

  “Right.”

  “But she wasn't born there?”

  “No. You know, you'll be able to ask her for her life's history directly, in a couple of minutes.”

  “Sorry.” Maybe it was absurd to be so curious about the newcomer when he still knew next to nothing about the Rindler's other passengers, but Yann's gloomy summary, and his own limited experience, had already made him long for someone who'd shake up the status quo.

  As they crossed the observation deck, the door to the recovery room opened. Tchicaya smiled in recognition at the newcomer's posture: loose-limbed and confident after the kinesthetic retuning, seizing up for a moment at the sight of the border.

  Then he recognized something more, and his own body turned to stone again.

  He didn't need to check her signature; she hadn't changed her appearance since their paths had last crossed. In fact, she hadn't changed in four thousand years, since the day they'd first parted.

  Tchicaya broke into a run, blind to everything around him, calling out her name.

  “Mariama!”

  She turned at the sound. He could see that she was shocked, and then uncertain how to respond. He halted, not wanting to embarrass her. It had been twelve hundred years since they'd set eyes on each other, and he had no idea what she'd make of his presence.

  Mariama held out her hands, and he ran forward to grip them in his own. They whirled around, laughing, surefooted on the polished floor, leaning back into their own centrifugal force, moving ever faster, until Tchicaya's arms ached and his wrists burned and his vision blurred. But he would not be the one to stop moving, and he would not be the one to let go.

  Chapter 6

  Something unseen stung Tchicaya's hand, a vibration like a tuning fork held against the bone. He turned and stared at the empty space beside him, and a dark blur shivered into solidity.

  “Quickly! Give your Exoself this code.”

  No sooner had the data passed between their Mediators than Tchicaya wished he'd rejected it. He felt as if he'd been tricked into catching something incriminatory thrown his way, the reflex action triggered by the object in flight turning out to have been the wrong response entirely.

  “I can't!”

  Mariama said, “No one will ever know. They're like statues. You'll be invisible.”

  Tchicaya's heart pounded. He glanced at the door, and caught himself straining his ears for footsteps, though he knew there'd be nothing to hear. Could she have really walked through the house undetected, marching right past his parents in that scandalous state?

  “Our Exoselves scan for danger,” he protested. “If anything happens at ordinary speed—”

  “Did your Exoself detect me?”

  “I don't know. It might have.”

  “Did it signal you? Did it bring you out of Slowdown?”

  “No.” He wasn't an adult, though. Who knew how differently theirs were programmed?

  “We'll stay clear of them,” Mariama explained. “I'm not doing this to pick their pockets. If we're not a threat to anyone, we won't trigger any alarms.”

  Tchicaya stared at her, torn. He had never feared his parents, but he basked in their approval. It only took the faintest shadow of disappointment on his father's face to make him ache with unhappiness. His parents were good people; valuing their high opinion was not just childish narcissism. If he did well in their eyes, he would be respected by everyone. Mariama was only Mariama: a law unto herself.

  She inclined her head. “Please, Tchicaya. It's fun doing this, but I'm lonely without you.”

  “How long have you been out of Slowdown?”

  Mariama averted her eyes. “A week.”

  That hurt. How lonely could she be, if it had taken her a week to miss him?

  She put a hand over her mouth and mumbled, “Or two.”

  Tchicaya reached out to grab her arm, and she danced back and vanished from sight. He froze for a second, then rushed for the door, and stood with his back pressed against it.

  He searched the room with his eyes, knowing that it was pointless looking for her if she did not want to be seen. Shadows slid across the walls and floor with hypnotic regularity. Lighting panels in the ceiling came on at night, and softened the changes at dusk and dawn, but even when he looked away from the window the diurnal cycle was obvious, everywhere.

  Another week had passed, while he stood there. She could not still be in the room with him; even if she was able to go that long without food and water, she would have gone mad from boredom.

  She reappeared in front of him like a trembling reflection in a pan of water, jolted into turbulence but quickly stilled.

  “How did you get in?” he demanded.

  She pointed a thumb at the window. “The same way I left.”

  “You're wearing my clothes!”

  Mariama grinned. “They fit me nicely. And I'm teaching them lots of new tricks.” She ran a hand down one sleeve and erased the old pattern, supplanting it with golden starbursts on black.

  Tchicaya knew she was goading him, hoping to prod him into giving chase. She'd handed him the key; he didn't need anything more in order to pursue her. If he gave in and joined her now, at least he'd be spared an elaborate game of hide-and-seek.

  He said, “Two weeks.” That sounded more than generous, and the risk of his parents noticing his absence would be microscopic.

  “We'll see.”

  Tchicaya shook his head. “I want you to agree to it. Two weeks, then we both come back.”

  Mariama chewed her lower lip. “I'm not going to make a promise I might not be able to keep.” Then she read his face, and relented slightly. “All right! Barring exceptional circumstances, we'll come back in two weeks.”

  Tchicaya hesitated, but he knew that this was the closest thing to a guarantee he could hope to extract from her.

  She held out a hand to him, smiling slightly. Then she silently mouthed the word Now.

  Their Mediators were smart enough to synchronize the process without needing to be told. Tchicaya sent the code to his Exoself, and the two of them dropped out of Slowdown together. Switching the metabolic modes of cells throughout his body, and reconfiguring all the higher-level systems responsible for maintaining posture, breathing, circulation, and digestion took nearly fifteen minutes. The time passed imperceptibly, though, since his Qusp only resumed its normal rate once his body had completed the shift.

  The light in his room had frozen into a late-winter's afternoon. He could hear a breeze moving through the trees beside the house, a different sound entirely to the throb of barometric pressure changes to which he'd grown accustomed. They were only six civil days into the Slowdown, but the new rhythms had seeped into his mind more rapidly than they'd had any right to, as if abetted by some process that his Exoself had neglected to retard.

  Mariama tugged on his hand, pulling him toward the door. “Come on!” Her expression made a joke of it, but she couldn't disguise the note of genuine impatience. They were like lightning now, their least purposeful meanderings a dazzling feat in everyone else's eyes, but that still wasn't fast enough.

  “Not that way.” He gestured at the window.

  Mariama said accusingly, “You're afraid to walk past them.”

  “Of course.” Tchicaya gazed back at her calmly. It was perfectly reasonable not to want to be discovered, and however skillful she was at manipulating him, he wasn't going to be made ashamed of every last instinct of his own. “It's safer to use the window. So we'll use the window.”

  Mariama managed to look both amused and martyred, but she di
dn't argue. Tchicaya climbed out, then she followed him, carefully pulling the hinged pane closed behind her. He was puzzled for a moment; no one was going to notice an open window in the short time they'd be gone. But in two weeks, the night frosts would have left an indelible mark on some of his more fragile possessions.

  As they crossed the garden, he said, “Don't you go home to sleep?”

  “No. I've set up camp in the power station. All my food's there.” She turned to face him, and Tchicaya was sure she was on the verge of demanding that he go back to the house to pilfer some supplies of his own, but then she said, “You can share it. I've got plenty.”

  The bright afternoon was eerily quiet, though Tchicaya doubted that he would have been unsettled if he'd heard no other voices for a minute, or an hour, on an ordinary day. As they stepped onto the road, he spotted two other pedestrians in the distance. During Slowdown, his Exoself had not only reprogrammed his own gait, it had tweaked his expectations of other people's appearance: moving with both feet constantly on the ground, positioning the arms to maximize stability, had looked as normal as it had felt. With his old notions of bodily dynamics restored, the pedestrians appeared, not merely frozen, but cowed and timid, as if they expected an earthquake at any moment.

  He looked back at his house, quickly lowering his eyes from the windows to inspect the garden. Wind and rain could shift soil and pebbles into unwanted places on a time scale of decades, but the plants were engineered to herd those unruly elements; he'd watched the process with his own eyes. Out in the fields, the crops would be tending themselves, collectively arranging whatever changes they needed in irrigation and drainage, glorying in the strange seasons of unharvested bounty.

  Tchicaya said, “How did you find the code?” It was the first Slowdown for both of them; she couldn't have stored it on a previous occasion.

  Mariama replied casually, “It's not a big secret. It's not buried deep, or encrypted. Don't you ever examine your Exoself? Take apart the software?”

  Tchicaya shrugged. He'd never even dream of tinkering with things on that level: his Exoself, his Mediator. Next thing you were probing the working of your own Qusp, dissecting your own mind. He said, “I only take things apart if I can survive not putting them back together.”

  “I'm not stupid. I make backups.”

  They'd reached the park. Four giant hexapods huddled motionless in a corner. The decorative robots consisted of nothing but six coiled legs, arranged as three pairs that met at right angles in the center. If they'd been endowed with even the mildest form of sentience, they would have gone insane from the lack of stimulation, but they were little more than pattern-recognizers on springs.

  Mariama ran up to them and clapped her hands. The nearest one stirred sluggishly, shifting its center of mass and wobbling on the tripod of the three legs currently touching the ground. She started dancing back and forth, encouraging it, and it began to tumble for her.

  Tchicaya watched, laughing, biting back an admonition: someone would notice that they'd moved, and know that the Slowdown had been violated. He doubted that the hexapods had memories, but there was machinery everywhere, monitoring the streets, guarding the town against unlikely dangers. The fact that they hadn't woken anyone didn't prove that they wouldn't be found out in the end.

  Mariama weaved between the robots. “Aren't you going to help me?”

  “Help you do what?” She'd managed to get all four of them moving simultaneously, without his aid. Tchicaya hadn't played with them since he was an infant, but he'd never been able to hold the attention of more than one at a time.

  “Make them collide.”

  “They won't do that.”

  “I want to get their legs tangled together. I don't think they understand that that can happen.”

  “You're a real sadist,” he protested. “Why do you want to confuse them?”

  Mariama rolled her eyes. “It can't hurt them. Nothing can.”

  “It's not them I'm worried about. It's the fact that you enjoy it.”

  She kept her eyes on him without breaking step. “It's just an experiment. It's not malicious. Why do you always have to be such a prig?”

  Tchicaya felt a surge of anger, but he fought it down and replied pleasantly, “All right, I'll help you. Tell me what to do.” He caught the flicker of disappointment in her eyes before she smiled and started issuing detailed instructions.

  The hexapods were primitive, but their self-and-environment model was more reliable than Mariama had imagined. After fifteen minutes trying to trick them into tying their legs into knots, she finally gave up. Tchicaya collapsed on the grass, breathless, and she joined him.

  He stared up into the sky. It had grown pale already, almost colorless. It had been summer when the Slowdown began; he'd forgotten how short the winter days were.

  Mariama said, “Has anyone you know even heard of Erdal?”

  “No.”

  She snorted, her expectations confirmed. “He probably lives on the other side of the planet.”

  “So? Do you want half the planet to go into Slowdown, and the other half not?” Everyone on Turaev was connected somehow. While Erdal traveled, the whole world would wait for him, together. It was either that, or they broke into a thousand shards.

  Mariama turned to face him. “You know why they do it, don't you?”

  It was a rhetorical question. People always had an ulterior motive, and Tchicaya had always been taken in by their explanations. He squirmed like an eager child and asked with mock excitement, “No, tell me!”

  Mariama shot him a poisonous look, but refused to be sidetracked. “Guilt. Cosmic apron strings. Do you think poor Erdal would dare not come home, with nine million people holding their breath for him?”

  Tchicaya knew better than to dispute this claim directly; instead, he countered, “What's so bad about Slowdown? It doesn't hurt anyone.”

  Mariama was venomous. “While every other civilized planet is flowering into something new, we do nothing and go nowhere, ten thousand times more ponderously than before.”

  “Lots of other planets do Slowdown.”

  “Not civilized ones.”

  Tchicaya fell silent. A faint star had appeared directly above him, even before the sun had fully set.

  He said, “So you'll leave one day? For good?” The question produced an odd, tight sensation in his windpipe. He'd never lost synch with anyone; he couldn't imagine that kind of unbridgeable separation.

  “No.”

  He turned to her, surprised. She said, “I plan to whip the whole planet into life, instead. Anything less would just be selfish, wouldn't it?”

  The machinery inside the power station was robust and intelligent enough to defend itself, and to safeguard any visitors, without the need for high fences or locked doors. Tchicaya remembered the place as being noisier the last time he'd explored it, but Slowdown had reduced the flow of waste from the town to an inaudible trickle. Energy was extracted from the waste by an enzyme-driven electrochemical process that he was yet to study in detail; fortunately, some of the energy ended up as heat, and even the diminished output was enough to make the building habitable at night. Mariama had made a nest of blankets right up against the coolant pipes that led to the radiator fins on the roof.

  Tchicaya sniffed the air cautiously, but there was no trace of the usual offensive odor, maybe because there was not only less sewage passing through, but the undiminished runoff from the fields was diluting it. There was a strange, boiled-vegetable smell to the place, but it was nothing he couldn't tolerate.

  Mariama had stockpiled cans of food, self-heating rations of the kind people took into the untouched, frozen lands to the south. It must have taken her a while to build up the collection without attracting suspicion. She handed him a can, and he pressed the tab to start it heating.

  “How long were you planning this?” he asked.

  “A bit more than a year.”

  “That's before I even knew Erdal would be trav
eling.”

  “Me too. I just wanted to be prepared, whenever it happened.”

  Tchicaya was impressed, and a little daunted. It was one thing to watch the sun and the stars racing around the sky, and think: what if I could be as fast as them? Plotting to break out of Slowdown before she'd even experienced it required an entirely different line of thought.

  “What were you doing? Before you came to my house?”

  She shrugged. “Just exploring. Messing about. Being careful not to wake the drones.”

  Tchicaya felt his face harden at this contemptuous phrase, but then he wondered how much allowance to make for the fact that she was always striving to provoke him. The calculations became so difficult at times, it drove him mad. He wanted the two of them to be straightforward with each other, but he doubted that would ever be her style. And he didn't want her to be different, he didn't want her to change.

  He opened the can and hunched over his meal, unsure what his face was betraying.

  After they'd eaten, they switched off the lamp and lay beneath the blankets, huddled together. Tchicaya was self-conscious at first, as if the contented glow he felt at the warmth of her body against his was at risk of turning into something more complicated, but he knew that it was still physically impossible for anything sexual to happen between them. The prospect of that guarantee eventually failing disturbed him, but it couldn't vanish overnight.

  Mariama said, “Two weeks isn't long enough. You need to walk out of your room a centimeter taller: just enough to make your parents feel something is wrong, without being able to put their finger on it.”

  “Go to sleep.”

  “Or learn something you didn't know. Amaze them with your erudition.”

  “Now you're just mocking me.” Tchicaya kissed the back of her head. He immediately wished he hadn't done it, and he waited, tensed, for some kind of rebuke. Or worse, some attempt to move further along a path on which he'd never meant to set foot.

  But Mariama lay motionless in the darkness, and after a while he began to wonder if she'd even noticed. Her hair was thick at the back, and his lips had barely brushed a few loose strands.