Dichronauts

by Greg Egan

  Seth thought of Elena, binding Irina in the hope of silencing her. And what would happen if a mob harassing a supposed Sleepwalker graduated from a supposed test of the condition to a supposed cure?

  Amir said quietly, “We need to be stronger than Thanton. We need to swallow this whole and spit out the poison, without being poisoned ourselves.”

  For a while everyone was silent, but then Judith replied, “That’s what we need, but need alone is not enough to make it true.”

  seth had feared that the problem of Thanton might keep him from sleep, but he lost consciousness the moment he lay down and didn’t stir until Amir nudged him and he opened his eyes to see that it was already mid-morning. Theo woke, under protest. «We’re owed two nights and a day.»

  «When we’re home,» Seth promised.

  Everyone else had already eaten breakfast, and Sarah and Raina had taken down their tent. Seth ate quickly, then helped Amir finish packing.

  As they set out again, Seth felt stronger for the rest, but his disquiet had deepened. “Maybe some other expedition will have found a river closer to home,” he said. Then Thanton and its poisonous forest need never be more than the subjects of an obscure travelers’ tale.

  “Anything’s possible,” Judith conceded.

  “It’s unlikely,” Raina declared. “Sedington would have found it first, and even if they didn’t want to share the news, I doubt they’d be digging for groundwater quite so energetically if they had.”

  “You really believe that?” Sarah sounded angry. “We’re the only team that ever stood a chance?”

  “That’s why I asked for the job,” Raina replied. “After the steamlands, they offered me my pick. And I wasn’t going to waste my time on anything but the farthest to the west.”

  “So why are you wasting your time now?”

  “What do you mean?” Raina didn’t seem offended, just perplexed.

  Sarah said, “We haven’t gone as far to the west as we might have. Why come all this way, only to turn around at the first opportunity, when we could keep going and look for something better?”

  Seth was expecting Raina to respond with a curt, dismissive rebuke: they’d fulfilled their duty as surveyors, and Thanton was a problem for the diplomats to solve.

  But instead, she was silent for a long time before replying, “Why don’t we put it to a vote?”

  Theo said, “We can’t lie about Thanton, vote or no vote.”

  “I’m not suggesting that,” Raina assured him. “But Sarah’s made a fair point: there’s no reason why we can’t return with more than one option. If there’s a second river farther to the west, and it’s unclaimed, or the locals are friendlier, that could make the migration a thousand times easier. It won’t be a matter of concealing anything: the wiser choice will be obvious.”

  Aziz said, “Nobody’s dragging me back toward Thanton again.”

  Raina had no such intention. “We can stay on the north side of the forest until we’re far to the west of Thanton, then we can head down toward the steamlands. If they’ve sent people after us, that would be the perfect way to lose them; they’d never expect us to loop around like that.”

  Seth listened with mixed emotions. He was eager to get home, and Baharabad needed to escape the drought by whatever means possible. The search for the perfect river could not go on forever.

  But the taint of Thanton was no small thing. He wanted to believe that the vast majority of his fellow citizens would prove honorable, but the whole of Baharabad didn’t need to succumb for the poison to wreak havoc. If his job was to find the best path for the city, it would not be complete until he was sure he hadn’t needlessly risked engendering disharmony between Walkers and Siders.

  Amina said, “You know my position. We need to come back in force and deal with this sickness once and for all: occupy the city, impose our own laws, harvest every noxious plant and burn it. It might take generations before these people’s descendants are normal again, but if we don’t act now, the problem is only going to spread.”

  “And from where will you raise this occupying force,” Judith wondered, “in which every last Walker will do what you demand, without a trace of sympathy for the people you expect them to control?”

  “Fuck their sympathy,” Amina replied. “They’ll follow orders or face the consequences.”

  “Or rebel and make common cause with Thanton,” Judith countered. “The more harshly we treat Thanton, the more we risk turning our own Walkers against us. As you say, it’s going to take generations, but a far safer way would be to live apart from these people, while offering them a chance to migrate to a more prosperous city if they’re willing to change their ways.”

  Amina was scathing. “So you want this abomination ended on a strictly voluntary basis?”

  Judith was undeterred. “If possible. We should at least try that, and see how it goes. Apart from anything else, it might take us a while to learn how to deal with adult Siders who’ve been drugged for their whole life. Better to start with dozens whose Walkers will cooperate with the process, than thousands whose Walkers will frustrate it in every way they can.”

  By mid-afternoon, as they passed to the north-east of the forest, everyone had had their say many times over. Every argument had been expounded in detail, every counter-argument raised, criticized, elaborated and dismissed.

  Raina called a vote.

  Amina and Aziz, unswayed by the debate, still wanted to return to Baharabad immediately. But the rest of the team voted to head west and continue the search.

  10

  Along the edge of the steamlands, a narrow, verdant band stretched as far to the east and west as the eye could see. To the north lay barren, windswept sand, to the south an expanse of desiccated mud where the night’s rain had pitted the ground then vanished in the heat of day. But weaving through the lush grass between them, a thousand tiny creeks glinted in the sun.

  As the expedition drew closer, the sight of this vast corridor of greenery filled Seth with hope. It was true that all the creeks in his immediate view dried out as they ran into the desert, because their flow was divided so finely, shared along so many paths. But how rare could it be for weather and landscape to conspire to consolidate these trickles into something more resilient?

  They trudged westward through the enervating heat, skirting the northern edge of the grassland. In Theo’s view, Seth could see the vegetation quivering as mice and lizards fled from unfamiliar footsteps. The shiny streams that had caught his eye from a distance proved almost comically warm and shallow; when he squatted down to try to fill his canteen, instead of immersing the container he had to scoop water in with the lid. The grass had a tough, slippery coating, unlike anything he’d encountered before, and when he tried to pick and eat a berry the first task almost broke his fingers and he abandoned the second before it damaged his teeth. He’d been wondering why no one chose to live in this borderland, but even if they could acclimate to the heat, the problem would be to coax something edible into growing here.

  When evening approached they could hear the rain begin falling to the east, and as they set up their tents the distant patter grew nearer, but only the faintest spray touched their skin. Theo’s pings to the south could just reach the edge of the downpour; much later, Seth woke in the darkness to the sound of water flowing nearby.

  When they set out again, shortly after dawn, the creeks were running ankle deep, but by mid-morning Seth was ladling water with his canteen lid again. Threads of shimmering liquid criss-crossed his view, far into the distance; for all he knew, this outlook continued unchanged halfway around the world. But beneath the hot sun his thirst was incessant, and if no one could die from lack of water here, however much he drank he never felt that his need had been slaked.

  The next night, when the noise of the runoff dragged him from sleep, Seth rose and went to refill his canteen. A part of him understood that the amount he had on hand could easily have lasted until morning, but the urgency that th
e task took on by daylight had entrenched itself too deeply to ignore.

  «I should make you do this blind,» Theo grumbled, but he pinged the nearest rivulet and guided Seth’s footsteps toward it through the clumps of grass.

  As they made their way back, Seth saw Raina and Amina standing in the open, very still.

  Amina said, “There’s a huge storm to the west.”

  “Where?” Seth asked.

  “Too far to see, but I can hear it.”

  He waited for confirmation from his Sider, but Theo could only defer to Amina’s expertise.

  Seth said, “That’s a good sign, surely?”

  “It was there last night,” Raina replied. “If it repeats for a few more nights, then it’s probably a feature of the landscape, not just a vagary of the weather.”

  As Seth lay down again and tried to sleep, he pictured the distant rain battering the ground. If the topography was unfavorable, all that water might flow south into the depths of summer and be lost. But his thirst would draw it north, whether it flowed with gravity’s help or not. His thirst alone was strong enough to make a river.

  “the storm’s still striking the same place, but we’ve passed it to the west.”

  Seth glanced toward Sarah and Amir to try to judge their reaction to Raina’s verdict, but their faces were locked in the same rigid expression that he felt on his own: a kind of preemptive tightening that reminded them all not to open their mouths and lose the slightest trace of moisture unless it was absolutely necessary.

  “That’s it, then?” Theo asked indignantly. “For seven days you’ve been telling us that it’s the biggest downpour you’ve ever heard . . . and now we’re meant to believe that it’s falling without a trace?”

  “It’s clear that there’s no river,” Amina replied. “Wherever the stormwater’s going, it’s not getting out of the steamlands.”

  Judith said, “Not right now—but we don’t know how small a shift it might take to change that.”

  “Or not,” Amina countered. “If it’s falling on a long southward rise, whether the storm maintains its solar latitude, or whether it’s tied more strongly to the topography, nothing’s going to bring that water north.”

  “So we need to find out,” Judith insisted. “We don’t turn around and go home without knowing the answer.”

  Aziz said, “You want to go into the steamlands and map this storm’s catchment area?”

  “Yes.”

  Seth looked to Raina. “It should be possible,” she said. “We know more or less where it is, and I don’t believe it’s so far south that it’s unreachable.”

  “Then we need to do this,” he replied. Raina and Amina had survived their trip into the northern steamlands; with that experience to guide them, what was there to fear? “Can we put it to a vote?”

  Raina said, “We can vote, but I’m not forcing anyone to go in, no matter what the majority decide.”

  “So it’s a matter of who volunteers?” Sarah asked.

  “Yes.”

  The vote fell exactly the same way as the last one: only Amina and Aziz were against proceeding. But this time, their power of veto over their Walkers doubled the effective size of their bloc. Seth and Theo, Sarah and Judith were free to walk into the steamlands, but Raina, with all her experience, had no choice but to stay behind.

  «I bet you’d like some of those Thanton puffballs to hand out right now,» Theo said dryly.

  «Don’t even joke about it.»

  Raina said, “If you travel at night and take shelter in the daytime, you ought to be able to get the whole thing done in two nights and a day.”

  seth sat resting on the east side of his tent, watching its shadow grow longer. His pack was prepared, with a minimum of food and four empty canteens. Even if they didn’t find the storm before sunrise, the ordinary night rains would be more than enough to fill the containers.

  «Remember when we thought that crossing the midwinter circle would make us surveyors?» he asked Theo.

  «It did.»

  «No, we’re only surveyors if we find a place where the city can flourish. Anything less, and we’re just two idiots who went for a long hike.»

  «Whatever maps we take back to Baharabad,» Theo said, «the city’s not going to perish. We might end up sharing a river with Thanton, or we might end up making some deal to join the Orico, but we’re too big to die.»

  «Not like all those cities in the history books?»

  «Their people didn’t die, they just found new homes.»

  «Some of them,» Seth conceded. «Not all.»

  As sunset drew near, he went looking for Sarah and Judith. He found them at the edge of the camp, talking to Raina and Amina.

  “What’s the one thing you forgot to tell us because it was too obvious?” he asked Raina.

  “Don’t get lost?” she suggested.

  “That sounds right.” Seth had grown used to finding his way back and forth across near-featureless deserts, but if he was going to be sidling through driving rain over ground endlessly reshaped by mudflows, he could not rely on old habits to fulfill even that basic tenet.

  He tipped his head back to face Sarah and Judith.

  Sarah said, “We’re ready.”

  the creeks near the campsite had all but dried out, but the four surveyors followed the widest slick of water south, since it marked a clear path through the vegetation. They moved without talking, concentrating on their footing. Seth could hear the rain starting in the east as twilight swept over the steamlands.

  By the time they crossed from grassland to mud, dusk had robbed Seth of his own vision, while the warm, heavy rain played havoc with Theo’s. The sheer density of the droplets was surreal; it was like being enfolded in endless layers of beaded curtains. South of the steamlands, water could not exist at all as a separate fluid—but vast quantities were present in latent form, dissolved in the searing air. When winds from the south carried that air to cooler climes the water would precipitate out, and the steamlands were first in line, generating more rain than anywhere else. All it would take to start a river here would be a reliable fall and a suitable catchment—modest requirements for an outcome that could bring prosperity to thousands of people. Seth was inured to the world’s indifference to his needs, but this did not seem too much to hope for from chance alone.

  «Can you hear it?» Theo asked.

  «Hear what?» To Seth, the rain around them dominated every sense. He shook his head to try to clear Theo’s pingers, and for an instant their surroundings grew sharper, but a moment later the membranes were drenched again.

  «Amina’s storm. It sounds almost subterranean.»

  Seth stood still and listened through his bones; either the distant pounding of the storm was hovering at the edge of his perception, or he was letting himself succumb to Theo’s suggestion. Subterranean? «Maybe the sound travels better through rock than through air.» He started sidling again, catching up with Sarah and Judith.

  As they slogged their way south across the softening mud, the trembling in the ground intensified.

  “Am I confused,” Seth shouted, “or have we been going downhill ever since we entered the steamlands?” It was a subtle slope, hard to judge by foot alone in the dark, but now he’d spent at least an hour splashing through trickling water that was all flowing north.

  “That’s right,” Sarah yelled back.

  The trickles had grown stronger as the night wore on, but now, though the rain around them was steady, the runoff was actually lessening, suggesting that as they moved south they were seeing the flow from a smaller catchment.

  “So why isn’t the storm sending anything north?” he asked.

  “We must be coming to the bottom of a valley. The storm must be falling on the opposite slope.”

  Seth couldn’t argue with her logic, and he couldn’t expect Theo to be pinging that distant slope through the rain. But if the storm was battering one side of a valley, and they were near the bottom, he would have
expected the sound to be coming from somewhere higher than the rock beneath their feet.

  Still, the long northward rise could serve as a conduit to bring the stormwater out of the steamlands, if it ever found its way across the valley. Once they’d mapped the whole area for the hydrologists to study, there might yet be hope of a new river for Baharabad.

  Judith shouted, “Stop!”

  Seth complied, peering into Theo’s view to try to discern the cause of her concern. For most of the night the ground a dozen paces ahead had been rendered indistinct by the intervening rain, so he’d focused all his attention on closer terrain, where the view was sharper and the need for information more pressing.

  But now, just before the point where Theo’s valiant attempts to ping the ground lost their battle with the rain, it looked very much as if the ground itself had ceased participating in the process. It wasn’t so much shrouded or blurred as absent.

  Seth sidled a couple of steps closer. If they’d reached the bottom of a rain-soaked valley, there might be some unusual scouring process at work where the runoff switched direction—not just carrying mud away, but carving a pit into the rock itself.

  From his new vantage point he could confirm, at least, that this wasn’t some narrow trench they could step over: as far to the south as Theo could show him, the ground remained too low to ping. But the pit might have been a dozen paces wide, or a hundred.

  “Let’s see if we can get around it,” Sarah suggested.

  They headed east cautiously, walking into darkness but letting the edge of the pit guide them. Seth watched the trickles of water that disappeared and reappeared in Theo’s view, alert for any sudden disparity suggesting more broken ground.

  No new hazards appeared in front of them, but the sharp drop on their right persisted. After half an hour, Seth lost patience. “This thing might go on forever, but how deep can it be? Maybe we can clamber down into it and sidle across.” If it had been filled with water, they would have heard rain striking the surface.

  Sarah said, “Why not throw something in and count the time till it hits bottom?”