Dichronauts

by Greg Egan

  “Poor Iqbal,” Seth replied. “It’s a horrible thing to have to hear. It’s going to be hard for a lot of people.”

  “I wish we’d got here sooner,” Dahlia said sadly. “We could have helped. We could have stopped it.”

  “Maybe.” Seth felt like a hypocrite; he shared her sympathy for the Southites, but he was also desperately searching for a strategy, if not to undermine it, at least to put it in the context of the risks that thousands of Walkers and Siders also faced. “But now that they know about the people trying to ambush them, they can be better prepared.”

  Dahlia said, “They still don’t know about it at the old home!”

  “No,” Seth agreed. “But the people here will get a message to them as soon as they can. After that, all the travelers will know to take precautions.”

  “Precautions?” For a moment Seth wondered if the word was unfamiliar to her, but she seemed to catch his meaning anyway. “We’re the precautions they need to take.”

  Ada shot Seth a glance suggesting that this was a conversation she’d already attempted. But Seth persisted. “What you did to protect our friends was amazing,” he said. “They must be grateful, and I’m certainly proud of you. But they’d had no warning that the attack might be coming. If they’d known, there must have been other things they could have done to keep themselves safe: choosing a different route, or spreading out more to make it harder to be ambushed.”

  “But they already knew it might happen,” Dahlia replied. “When the travelers from the old home didn’t arrive, that’s what everyone was afraid of.”

  Seth was taken aback. He looked away, out across the settlement, at the people gathering in mourning. Maybe it was pure hindsight, but now it struck him that they did not appear as shocked or agitated as they would have if the news had been entirely unexpected. “When did they tell you that? Before the attack, or after?”

  Dahlia said, “After.”

  “All right.” Seth wasn’t sure how angry he should feel. No one had forced them to join the search party, and it had been his responsibility to ask the right questions before tagging along. For all he knew, the Southites might have thought it would be blindingly obvious, even to their guests, that if a group of travelers had gone missing, whoever went looking for them would be in peril too. In his conversations with Iqbal and Siméon, all his efforts had gone into making it clear how important the measurements of the chasm were to him. If they’d read that as an emphatic declaration that he was committed to the task despite the manifest dangers, who were they to argue?

  “The only thing they told me before was to keep watch for anything from above,” Dahlia added.

  Seth needed a second opinion. «So they were using us all along?»

  «It looks that way,» Theo replied. «But what else would you expect? They’ve lost more than a hundred people, and they’re facing a war that might wipe them out completely. Thanton wasn’t facing any kind of danger—and they still felt they had a right to make their Siders shut up and serve their masters in silence.»

  «Yeah.» But if the Southites were understandably desperate, Seth took some hope from the fact that their reasons had not been petty or malevolent; it didn’t follow that they’d be crueller than the Thantonites. «We know they put us in with the search party in the hope that we could protect them, but everything else is supposition. Until we’ve actually come right out and asked them to help us get home, we’re just guessing as to what they’d say.»

  Theo didn’t reply, but Seth didn’t need to be told that it was going to be a struggle to win Dahlia over to the idea, let alone anyone else.

  He resumed the conversation with her. “You know that in the part of the world where Ada and I can walk, there’s a migration too?”

  “Yes.” Dahlia was impatient. “That’s why you had to find out the size of the hole. I understand that.”

  “The good news we found, though,” Seth persisted, “won’t do much good if no one else knows about it. What I did to measure it wasn’t too hard—thanks to all the help I got from Iqbal and Siméon—but back where we came from, that would have been impossible. If we don’t take the news back soon, people could die trying to get that information, and maybe from trying other things that they think they need to do, but we know they really don’t.” The last part sounded vague to the point of meaninglessness, but how could he explain the risks of building a bridge of balloons over the node to someone who’d only been conscious in this hyperboloid?

  “Why would anyone die trying to find the size of the hole?” Dahlia demanded. “They can just come here like you did.”

  Seth said, “Coming here wasn’t easy. When we started out, there were six other people with us. We got separated in the river; I don’t know where they are now. I would have searched for them if I could, but the only way to travel is by boat, and the water moves so fast that you have no choice but to let it carry you along.”

  Dahlia hesitated. “Why didn’t you tell me that before?”

  Ada said, “We didn’t want to make you sad.”

  Dahlia wasn’t satisfied. “Theo?”

  “It’s true,” Theo said. “Sarah and Judith, Raina and Amina, Andrei and Nicholas. We were all together at the start of the journey, but a lot of bad things happened along the way.”

  Dahlia lapsed into silence. Seth decided not to push her; she needed time to take this in. He crawled over to the pile of food that Marco had left; the pain this produced in his shoulder was even worse than he’d been anticipating. He tossed some fruit to Ada; she picked it up gingerly and started to eat.

  Dahlia said, “I’m sorry about your friends. I hope they’re safe, wherever they are. But if we don’t help our friends here, all of them could die.”

  “They’ve survived without us for a very long time,” Seth replied. “And we can’t stay forever, you know that. They need to find a way to solve their problems on their own.”

  Dahlia was unswayed. “We can’t stay forever, but we can’t leave until we’ve done everything we can to protect them.”

  from the enclosure, seth watched the Southites preparing for a new expedition. Dahlia had explained its purpose, but it was exactly what he’d expected: the plan was to travel back to the old home in order to escort the next group of migrants on their journey to the settlement. In earlier times, they probably would have done the same thing in response to the attack, with the escort providing extra numbers to serve as scouts or soldiers, or whatever had been the best form of protection from being ambushed, before there were creatures who could see into the sky.

  «Don’t these idiots have diplomats?» Theo asked irritably. «We might kill each other over rivers sometimes, but at least we go through all the niceties first. And these chasms are visible for generations! They ought to have some protocol for deciding ownership, long before anyone actually makes the journey and tries to take possession of the land.»

  Seth thought it over. «Maybe they do. But what if the land around some chasm that looked promising from a distance turns out to be unfarmable?» Predicting temperature and illumination might come down to pure geometry, but spotting soil types from afar was another question.

  The reasons for the dispute didn’t matter, though; if the Southites hadn’t managed to make peace for themselves, Seth wasn’t deluded enough to think that he was going to step in and resolve the conflict when he couldn’t even speak the language.

  He said, «There must be some way that they can travel safely, without dragging along a Sider to see into the dark cone.» He stared at the open carts, loaded with supplies; they looked absurdly vulnerable now. «If the fact that we come from such a different place is enough to give us a sensory advantage here, maybe we have some other advantage that has nothing to do with our bodies: something in our material culture that the Southites don’t have, that we can hand over to them as a pure idea.»

  «I want to steal the idea behind their carts,» Theo replied. «I bet we could make something that runs north-south on a b
elt, if we put our minds to it.»

  «No doubt, but can we stick to ideas that we can offer them?»

  «They don’t seem to have balloons,» Theo observed. «If they were willing to try making the crossing through the air, their enemies would only be able to see them from afar. That might not make them invulnerable in the long run, but they could certainly get beyond the range of existing catapults.»

  Seth wasn’t going to dismiss anything out of hand. «They couldn’t control the balloons with ropes over such a long distance, but there’s no risk here of drifting into absolute summer; if you meander a bit, it’s not instantly fatal. The question would be whether or not there are winds at some altitude that would carry them where they needed to go.»

  «That, and whether they have the resources to weave that much fabric, and heat that much air. I doubt they could do it here, but the old home might have real forests and plantations.» Theo thought for a while, then added darkly, «Even if they could solve all those problems, though, they might want to hang on to our ability to see the ground directly below.»

  «They could navigate without that,» Seth replied. «They’d still be able to see most of the bowl.»

  «Yes, but I’m more worried that they’d want us to help them drop things on their enemies.»

  Seth glanced at Ada; since they’d returned, she’d begun sinking back into the listless state he recognized from the time when they’d first arrived in the hyperboloid. He wanted to include her in the discussion, but it was hard to talk freely when Dahlia was listening.

  «I suppose we could raise this with Siméon,» Theo suggested. «At least find out if it’s an invention that they’re aware of, and have already ruled out for long-distance travel, or whether it’s an entirely new idea here.»

  Seth had lost interest; he wasn’t going to flop around in the dirt for another thousands days while the Southites improved their weaving skills. «This has gone on long enough,» he said. “Dahlia?”

  “Yes?”

  “You need to tell Lana that we’re not joining the expedition to the old home. We’re going back to our own home. They can help us or not, but as far as we’re concerned what we did for the search party has more than repaid them for their kindness, and it’s time we parted company.”

  “We can’t leave!” Dahlia was horrified.

  “We need to.” Seth did his best to sound gentle but firm, like a loving parent correcting an errant child. “There’s too much at stake for our own people for us to stay any longer. We’ve already helped our friends here understand the situation they’re in, but now it’s up to them to make the best of it. They need to find a way to protect themselves without us.”

  “I’m not telling Lana any of that,” Dahlia replied vehemently.

  “And no one can force you to,” Seth conceded. “But Ada and I are the ones with limbs. We’re not going to be turning any cranks, and if they try to carry us, we’ll be struggling all the way.”

  Dahlia said, “You and Theo are useless anyway. You can’t speak the language, so there’s no reason to take you.”

  “Believe me, Ada has ways to make you every bit as useless.” Seth had no idea what Ada could actually do to back up that threat, but the words had spilled out regardless, as if he could summon the spectre of Thanton without ever having mentioned the place.

  “This is my family!” Dahlia’s tone was anguished now. “I’m not going to leave them to die!”

  “No one else is going to die,” Seth assured her, summoning all the false confidence he could, thankful that she’d only seen one bisected body and not the mass carnage of the larger ambush. “Lana and her friends know exactly what the danger is—and it’s something that their ancestors would have faced a thousand times before. Our families back home are facing a danger that no one’s ever experienced. They’re the ones who need us the most.”

  Dahlia fell silent, and Seth began to feel hopeful. The sheer numbers of the Southites and her immersion in their culture clearly carried a lot of sway, but she had to feel a special kinship with Theo, and a special bond with Ada. Once she turned her thoughts seriously to the unseen multitude of Siders and Walkers, she would understand where her loyalties belonged.

  She said, “You and Theo should go, then. But Ada and I need to stay.”

  “No. That’s impossible.” Seth fought to keep the horror from showing on his face. “You’ve never seen a Walker where they belong, but you’ve seen the difference between us and the Southites. You can’t expect me or Ada to stay here—even with the carts, even with the Southites doing their best to treat us well. We’re in pain here, all the time. Our bodies aren’t made for this place. If you care about Ada, you won’t try to force this on her: you’ll tell Lana that we’re all going home.”

  Ada said, “And Lana will agree to that . . . why?” She sounded grimly amused at the absurd overreach of his ambitions. But then, she’d sounded the same when he’d first dared to claim that they had any chance at all of surviving here.

  “I don’t know what they’ll agree to,” Seth conceded. “But we have to ask. Dahlia has to ask.”

  “I’m not asking to leave!” Dahlia retorted.

  “So you’re going to torture Ada? Keep her where she doesn’t belong, keep her away from all the people she misses?” Seth barely managed to stop himself before he embarked on a paean to all the love and protection that Ada had given her Sider. But however dishonest that would have been, Dahlia didn’t know a thing about Thanton and the puffballs. Her cruelty was no less thoughtless than it would have been if Ada really had been her mother, or her most loyal friend.

  “We won’t have to stay here forever,” Dahlia replied. “But I’m not going back until I know for sure that Iqbal will be safe.”

  Seth said, “You do know that you’ll be dead long before the migration is complete?” He was guessing, but the prediction wasn’t far-fetched; between the slow rate at which the land was thawing and the need to balance the workforce with the food supply, it could easily take a lifetime to increase the agricultural capacity to the point where everyone could come.

  “It won’t take that long to strengthen the settlement enough to make it safe,” Dahlia replied, which was probably an equally plausible guess. Seth was tempted to ask her to bring in a Southite to adjudicate, but though he trusted Iqbal to be honest, his knowledge was patchy, and all the better-informed adults had agendas and a record of deceit.

  Seth changed tactics. “The journey back is hard,” he said. “Ada’s had less experience as a traveler than I’ve had. If you and she try to come back on your own, and you get into trouble, the slope’s an unforgiving place.”

  Dahlia fell silent again. Seth looked away, hardly daring to hope that he might finally have got through to her. What the Southites would accept was another question, but he could only face one obstacle at a time.

  Ada said, “I’ll stay. If the Southites give Seth and Theo a boat and show them the currents north, then I’ll agree to stay here as long as we’re needed, helping Dahlia to protect the migrants.”

  “Don’t be ridiculous!” Seth wanted to slap her; they’d been so close to winning Dahlia over, and now she’d thrown that all away in a pointless gesture of self-abnegation.

  “It’s what I want,” Ada said calmly. “There’s nothing left for me back home.” She met Seth’s gaze directly as she spoke, and his skin tingled as he understood the message behind her words. No one would accept her in Thanton, with a Sider that had woken from its sleep. But whether she lived in Thanton or anywhere else, Dahlia would soon learn what her Walker had done to her, and that would be unbearable for both of them.

  Ada smiled slightly, seeing that he understood. What did Seth expect her to do? Return to Thanton and send Dahlia back into oblivion? Or share her skull for the rest of her life with a Sider who had every reason to despise her?

  “I’ll talk to Lana, and ask her about the boat,” Dahlia announced triumphantly. “I’m sure she’ll agree, I’m sure!”


  Seth lay staring at Ada, at a loss for words.

  “I’ll miss you and Theo,” Dahlia said. “But I know you have to leave, to help all those people. This way, you can keep everyone safe back home, and Ada and I can help everyone here. I’m just so happy that we finally worked it out!”

  20

  Seth borrowed ada’s cart and drove it down to the river to watch the boat-builders at work. The line of lights had moved far away across the blue-gray bowl of the hyperboloid, but the dark water brought it back in broken, shimmering reflections, which stretched out into the distance until they vanished in the blackness of the chasm.

  The two-tiered design being assembled on the scaffolding was a compromise between the demands of flat water and those of the slope. Seth had given up on the idea of trying to create a more robust version of the system of sliding modules used by the boat that had brought him here, but once he was sure that he and Dahlia had successfully described the vessel’s needs he’d left it to the builders to choose the precise geometry, calculating buoyancies and ensuring that the whole thing would be stable throughout the journey. No one could promise that they’d survive every waterfall and every dunking, but he believed they’d stand at least as good a chance as they had in the flimsy box that they’d ridden on the way down.

  Four of the builders were laboring away now, shaping the boards of the timber hull; Seth stopped the cart and observed them in silence. It felt chilly by the water in the not-quite-night, but the Southites preferred it that way.

  He said, «As soon as it’s complete and they’ve loaded the supplies, we just need to find a way to get Ada and Dahlia down here alone, while the Southites are sleeping.»

  «They’re not going to let that happen,» Theo replied.

  «Are you sure? Because I have no idea what they’d do if we tried.» That was the most hopeful, most maddening part of it. Dahlia had flatly refused to translate anything that went beyond Ada’s proposal; the Southites had agreed to it, apparently quite willingly, but no alternatives had ever been raised. It was obvious where their self-interest lay, but they’d never been given a chance to demonstrate whether or not they were willing to rise above it.