4

First he had to learn the land. With that as his project it was amazing how busy every day became, there was an endless number of things to do; but no structure, no schedule, no rush; no one to consult; and every day, in the last hours of summer light, he would walk around the ridge, and inspect the basin in the failing light. It was already colonized by lichen and the other first settlers; fellfields filled the hollows, and there were small mosaics of arctic ground cover in the sunny exposures, mounds of green moss humped on red soil less than a centimeter thick. Snowmelt coursed down a number of rivulet channels, pooling and dropping through any number of potential meadow terraces, little diatom oases, falling down the basin to meet in the gravel wadi at the gate to the land below, a flat meadow-to-be behind the residual rim. Ribs higher in the basin were natural dams, and after some consideration, Nirgal carried some ventifacts to these low ribs, and assembled them with their facets touching so that the ribs were heightened by just one or two rocks’ height. Snowmelt would collect in meadow ponds, banked by moss. The moors just east of Sabishii resembled what he had in mind, and he called up ecopoets who lived on those moors, and asked about species compatibility, growth rates, soil amendment and the like. In his mind developed a vision of the basin; then in second March the autumn came, the year heading toward aphelion, and he began to see how much of the landscaping would be done by wind and winter. He would have to wait and see.

He spread seeds and spores by hand, casting them away from bags or growth media dishes latched to his belt, feeling like a figure from Van Gogh or the Old Testament; it was a peculiar sensation of mixed power and helplessness, action and fate. He arranged for loads of topsoil to be trucked up and dumped on some of the little fields, and then he spread it out by hand, thinly. He brought in worms from the university farm at Sabishii. Worms in a bottle, Coyote had always called people in cities; observing the writhing mass of moist naked tubules, Nirgal shuddered. He released the worms onto his new little plots. Go, little worm, prosper on the land. He himself, walking around on the sunny mornings after a shower, was no more than moist linked naked tubules. Sentient worms, that’s what they were, in bottles or on the land.

After the worms it would be moles and voles. Then mice. Then snow rabbits, and ermine, and marmots; perhaps then some of the snow cats wandering the moors would drop by. Foxes. The basin was high, but the pressure they were hoping for at this altitude was four hundred millibars, with forty percent of that oxygen; they were already most of the way there. Conditions were somewhat as in the Himalayas. Presumably all of Earth’s high-altitude flora and fauna would be viable here, and all the new engineered variants; and with so many ecopoets stewarding small patches of the upland, the problem would be mostly a matter of prepping the ground, introducing the basic ecosystem desired, and then supporting it, and watching what came in on the wind, or walked in, or flew. These arrivals could be problematic of course, and there was a lot of talk on the wrist about invasion biology, and integrated microcline management; figuring out one’s locality’s connections to the larger region was a big part of the ongoing work of ecopoesis.

Nirgal got even more interested in this matter of dispersal the next spring, in first November when the snows melted, and poking out of the late slush on the flat terraces of the northern side of the basin were sprigs of snow alumroot. He hadn’t planted them, he had never heard of them, indeed he wasn’t even sure of his identification, until his neighbor Yoshi dropped by one week and confirmed it: Heuchera nivalis. Blown in on the wind, Yoshi said. There was a lot of it in Escalante Crater to the north. Not much of it in between; but that was jump dispersal for you.

Jump dispersal, spread dispersal, stream dispersal: all three were common on Mars. Mosses and bacteria were spread dispersing; hydrophilic plants were stream-dispersing along the sides of glaciers, and the new coastlines; and lichen and any number of other plants were jump-dispersing on the strong winds. Human dispersion showed all three patterns, Yoshi remarked as they wandered over the basin discussing the concept— spreading through Europe and Asia and Africa, streaming down the Americas and along the Australian coasts, jumping out to the Pacific Islands (or to Mars). It was common to see all three methods used by highly adaptable species. And the Tyrrhena massif was up in the wind, catching the westerlies and also the summer trade winds, so that both sides of the massif got precipitation; nowhere more than twenty centimeters a year, which would have made it desert on Earth, but in the southern hemisphere of Mars, that was a precipitation island. In that way too a dispersion catchment, and so very invasible.

So. High barren rocky land, dusted with snow wherever shade predominated, so that the shadows tended to be white. Little sign of life except in basins, where the ecopoets helped along their little collections. Clouds surged in from west in the winter, east in the summer. The southern hemisphere had the seasons reinforced by the perihelion-aphelion cycle, so that they really meant something. On Tyrrhena the winters were hard.

Nirgal wandered the basin after storms, looking to see what had blown in. Usually it was only a load of icy dust, but once he found an unplanted clutch of pale blue Jacob’s ladders, tucked between the splits in a breadloaf rock. Check the botanicals to see how it might interact with what was already there. Ten percent of introduced species survived, then ten percent of those became pests; that was invasion biology’s ten-ten rule, Yoshi said, almost the first rule of the discipline. “Ten meaning five to twenty, of course.” Once Nirgal weeded out a springtime arrival of common streetgrass, fearing it would take over everything. Same with tundra thistle. Another time a heavy dust load fell on an autumn wind. These dust storms were small compared to the old global southern-summer storms, but occasionally a hard wind would tear up the desert pavement somewhere and send the dust below flying. The atmosphere was thickening rapidly these days, fifteen millibars a year on average. Each year the winds had more force, and so thicker areas of pavement were at risk of being torn away. The dust that fell was usually a very thin layer, however, and often high in nitrates; so it was like a fertilizer, to be washed into the soil by the next rain.

Nirgal bought a position in the Sabishii construction coop he had looked into. He went in often to work on the town’s buildings. Up in the basin he did some assembly and testing of solo blimpgliders. His work cottage was a small building made of stone-stacked walls, with plates of sandstone for shingles. Between that work and the farming in the greenhouse and his potato patch, and the ecopoesis in the basin, his days were full.

He flew the completed blimpgliders down to Sabishii, and stayed in a little studio above in his old teacher Tariki’s rebuilt house in the old city, living there among ancient issei who looked and sounded very much like Hiroko. Art and Nadia lived there too, raising their daughter Nikki. Also in town were Vijjika, and Reull, and Annette, all old friends from his student days— and there was the university itself, no longer called the University of Mars, but simply Sabishii College— a small school that still ran in the amorphous style of the demimonde years, so that the more ambitious students went to Elysium or Sheffield or Cairo; those who came to Sabishii were those fascinated by the mystique of the demimonde years, or interested in the work of one of the issei professors.

All these people and activities made Nirgal feel strangely, even uncomfortably, at home. He put in long days as a plasterer and general laborer on various construction jobs his co-op had around town. He ate in rice bars and pubs. He slept in the loft in Tariki’s garage, and looked forward to the days he returned to the basin.

One night he was walking home late from a pub, asleep on his feet, when he passed a small man sleeping on a park bench: Coyote.

Nirgal stopped short. He walked over to the bench. He stared and stared. Some nights he heard coyotes howling up in the basin. This was his father. He remembered all those days hunting for Hiroko, without a clue where to look. But here his father slept on a city park bench. Nirgal could call him anytime, and always that bright cracked grin, Trinidad itself. Tears started to his eyes; he shook his head, composed himself. Old man lying on a park bench. One saw it fairly frequently. A lot of the issei had gotten here and gone off somehow, into the back country for good, so that when they came into a city they slept in the parks.

Nirgal went over and sat on the end of the bench, just beyond his father’s head. Gray tatty dreadlocks. Like a drunk. Nirgal just sat with him, looking at the undersides of the linden trees around the bench. It was a quiet night. Stars ticked through the leaves.

Coyote stirred, twisted his head and glanced up. “Who dat.”

“Hey,” Nirgal said.

“Hey!” Coyote said, and sat up. He rubbed at his eyes. “Nirgal, man. You startle me there.”

“Sorry. I was walking by and saw you. What are you doing?”

“Sleeping.”

“Ha-ha.”

“Well, I was. Far as I know that was all I was doing.”

“Coyote, don’t you have a home?”

“Why no.”

“Doesn’t that bother you?”

“No.” Coyote bleared a grin at him. “I’m like that awful vid program. The world is my home.”

Nirgal only shook his head. Coyote squinted as he saw that Nirgal was not amused. He stared at him for a long time from under half-mast eyelids, breathing deeply. “My boy,” he said at last, dreamily. The whole city was quiet. Coyote muttered as if falling asleep. “What does the hero do when the tale is over? Swim over the waterfall. Drift out on the tide.”

“What?”

Coyote opened his eyes fully, leaned toward Nirgal. “Do you remember when we brought Sax into Tharsis Tholus and you sat with him, and afterward they said you brought him back to life? That kind of thing— think about that.” He shook his head, leaned back on the bench. “It’s not right. It’s just a story. Why worry about that story when it’s not yours anyway. What you’re doing right now is better. You can walk away from that kind of story. Sit in a park at night like any ordinary person. Go anywhere you please.”

Nirgal nodded, uncertain.

“What I like to do,” Coyote said sleepily, “is go to a sidewalk café and toss down some kava and watch all the faces. Go for a walk around the streets and look at people’s faces. I like to look at women’s faces. So beautiful. And some of them so . . . so something. I don’t know. I love them.” He was falling asleep again. “You’ll find your way to live.”

• • •

Guests who occasionally visited him in the basin included Sax, Coyote, Art and Nadia and Nikki, who got taller every year; she was taller than Nadia already, and seemed to regard Nadia like a nanny or a great-grandmother— much as Nirgal himself had regarded her, in Zygote. Nikki had inherited Art’s sense of fun, and Art himself encouraged this, egging her on, conspiring with her against Nadia, watching her with the most radiant pleasure Nirgal had ever seen on an adult face. Once Nirgal saw the three of them sitting on the stone wall by his potato patch, laughing helplessly at something Art had said, and he felt a pang even as he too laughed; his old friends were now married, with a kid. Living in that most ancient pattern. Faced with that, his life on the land did not seem so substantial after all. But what could he do? Only a few people in this world were lucky enough to run into their true partners— it took outrageous luck for it to happen, then the sense to recognize it, and the courage to act. Few could be expected to have all that, and then to have things go well. The rest had to make do.

• • •

So he lived in his high basin, grew some of his food, worked on co-op projects to pay for the rest. He flew down to Sabishii once a month in a new aircraft, enjoyed his stay of a week or two, and went back home. Art and Nadia and Sax came up frequently, and much less often he hosted Maya and Michel, or Spencer, all of whom lived in Odessa— or Zeyk and Nazik, who brought news of Cairo and Mangala that he tried not to hear. When they left he went out onto the arcing ridge and sat on one of his sitting boulders, and looked at the meadows stringing through the talus, concentrating on what he had, on this world of the senses, rock and lichen and moss campion.

The basin was evolving. There were moles in the meadows, marmots in the talus. At the end of the long winters the marmots came out of hibernation early, nearly starving, their internal clocks still set to Earth. Nirgal set out food for them in the snow, and watched from his house’s upper windows as they ate it. They needed help to get through the long winters to spring. They regarded his house as a source of food and warmth, and two marmot families lived in the rocks under it, whistling their warning whistle when anyone approached. Once they warned him of people from the Tyrrhena committee on the introduction of new species, asking him for a species list, and a rough census; they were beginning to formulate a local “native inhabitant” list, which, once formed, would allow them to make judgments on any subsequent introductions of fast-spreading species. Nirgal was happy to join this effort, and apparently so was everyone else doing ecopoesis on the massif; as a precipitation island, hundreds of kilometers from the nearest others, they were developing their own mix of high-altitude fauna and flora, and there was a growing sentiment to regard this mix as “natural” to Tyrrhena, to be altered only by consensus.

The group from the committee left, and Nirgal sat with the house marmots, feeling odd. “Well,” he said to them, “now we’re indigenous.”

• • •

He was happy in his basin, above the world and its concerns. In the spring new plants appreared from nowhere, and some he greeted with a trowel of compost, others he plucked out and turned into compost. The greens of spring were unlike any other greens— light electric jades and limes of bud and leaf, new blades of emerald grass, blue nettles, red leaves. And then later the flowers, that tremendous expense of a plant’s energy, the push beyond survival, the reproductive urge all around him . . . sometimes when Nadia and Nikki came back from their walks holding miniature bouquets in their big hands, it seemed to Nirgal that the world made sense. He would eye them, and think about children, and feel some wild edge in him that was not usually there.

It was a feeling generally shared, apparently. Spring lasted 143 days in the southern hemisphere, coming all the way back from the harsh aphelion winter. More plants bloomed as the spring months passed, first early ones like promise-of-spring and snow liverwort, then later ones such as phlox and heather, then saxifrage and Tibetan rhubarb, moss campion and alpine nailwort, cornflowers and edelweiss, on and on until every patch of green carpet in the rocky palm of the basin was touched with brilliant dots of cyanic blue, dark pink, yellow, white, each color waving in a layer at the characteristic height of the plant holding it, all of them glowing in the dusk like drips of light, welling out into the world from nowhere— a pointillist Mars, the ribbiness of the seamed basin etched in the air by this scree of color. He stood in a cupped rock hand which tilted its snowmelt down a lifeline crease in the palm, down into the wide world so far below, a vast shadowy world that loomed to the west under the sun, all hazy and low. The last light of day seemed to shine slightly upward.

One clear morning Jackie appeared on his house AI screen, and announced she was on the piste from Odessa to Libya, and wanted to drop by. Nirgal agreed before he had time to think.

He went down to the path by the outlet stream to greet her. Little high basin . . . there were a million craters like it in the south. Little old impact. Nothing the slightest bit distinguished about it. He remembered Shining Mesa, the stupendous yellow view at dawn.

They came up in three cars, bouncing wildly over the terrain, like kids. Jackie was driving the first car, Antar the second. They were laughing hard as they got out. Antar didn’t seem to mind losing the race. They had a whole group of young Arabs with them. Jackie and Antar looked young themselves, amazingly so; it had been a long time since Nirgal had seen them, but they had not changed at all. The treatments; current folk wisdom was to get it done early and often, ensuring perpetual youth and balking any of the rare diseases that still killed people from time to time. Balking death entirely, perhaps. Early, often. They still looked like they were fifteen m-years old. But Jackie was a year older than Nirgal, and he was almost thirty-three m-years old now, and feeling older. Looking at their laughing faces, he thought, I’ll have to get the treatment myself someday.

So they wandered around, stepping on the grass and oohing and ahhing at the flowers, and the basin seemed smaller and smaller with every exclamation they made. Near the end of their visit Jackie took him to one side, looking serious.

She said, “We’re having trouble holding off the Terrans, Nirgal. They’re sending up almost a million a year, just like you said they never could. And these new arrivals aren’t joining Free Mars like they used to. They’re still supporting their home governments. Mars isn’t changing them fast enough. If this goes on, then the whole idea of a free Mars will be a joke. I sometimes wonder if it was a mistake to leave the cable up.”

She frowned and twenty years jumped onto her face all at once. Nirgal suppressed a little shudder.

“It would help if you weren’t hiding here,” she exclaimed with sudden anger, dismissing the basin with a wave of her hand. “We need everyone we can get to help. People still remember you now, but in a few years. . . .”

So he only had to wait a few more years, he thought. He watched her. She was beautiful, yes. But beauty was a matter of the spirit, of intelligence, vivacity, empathy. So that while Jackie grew ever more beautiful, at the same time she grew less beautiful. Another mysterious infolding. And Nirgal was not pleased by this internal loss in Jackie, not in any way; it was only one more note in the chord of his Jackie pain, really. He didn’t want it to be true.

“We can’t really help them by taking more immigrants,” she said. “That was wrong, when you said that on Earth. They know it too. They can see it better than we can, no doubt. But they send people anyway. And you know why? You know why? Just to wreck things here. Just to make sure there isn’t someplace where people are doing it right. That’s their only reason.”

Nirgal shrugged. He didn’t know what to say; probably there was some truth to what she had said, but it was just one of a million different reasons for people to come; there was no reason to fix on it.

“So you won’t come back,” she said at last. “You don’t care.”

Nirgal shook his head. How to say to her that she was not worried about Mars, but about her own power? He wasn’t the one who could tell her that. She wouldn’t believe him. And maybe it was only true to him anyway.

Abruptly she stopped trying to reach him. A regal glance at Antar, and Antar did the work of gathering their coterie into the cars. A final questioning look; a kiss, full on the mouth, no doubt to bother Antar, or him, or both of them; like an electric shock to the soul; and she was off.

• • •

He spent the afternoon and the next day wandering, sitting on flat rocks and watching the little rivulets bounce downstream. Once he remembered how fast water had fallen on Earth. Unnatural. No. But this was his place, known and loved, every dyad and every clump of campion, even the speed of water as it lofted off stone and plashed down in its smooth silver shapes. The way moss felt under the finger pads. His visitors were people for whom Mars was forever an idea, a nascent state, a political situation. They lived in the tents and they might as well have been in a city anywhere, and their devotion, while real, was given to some cause or idea, some Mars of the mind. Which was fine. But for Nirgal now it was the land that mattered, the places where water arrived just so, trickling over the billion-year-old rock onto pads of new moss. Leave politics to the young, he had done his part. He didn’t want to do anymore. Or at least he wanted to wait until Jackie was gone. Power was like Hiroko, after all— it always slipped away. Didn’t it? Meanwhile, the cirque like an open hand.

• • •

But then one morning when he went out for a dawn walk, there was something different. The sky was clear, its purest morning purple, but a juniper’s needles had a yellowish tinge to them, and so did the moss, and the potato leaves on their mounds.

He plucked the yellowest samples of needles and sprigs and leaves, and took them back to the workbench in his greenhouse. Two hours’ work with microscope and AI did not find any problem, and he went back out and pulled up some root samples, and bagged some more needles and leaves and blades and flowers. Much of the grass had a wilted look, though it wasn’t a hot day.

Heart thudding, stomach taut, he worked all day and into the night. He could discover nothing. No insects, no pathogens. But the potato leaves in particular looked yellow. That night he called Sax and explained the situation. By coincidence Sax was visiting the university in Sabishii, and he drove up the next morning in a little rover, the latest from Spencer’s co-op.

“Nice,” Sax said as he got out and looked around. He checked Nirgal’s samples in the greenhouse. “Hmm,” he said. “I wonder.”

He had brought some instruments in his car, and they lugged them into the boulder and he went to work. At the end of a long day he said, “I can’t find anything. We’ll have to take some samples down to Sabishii.”

“You can’t find anything?”

“No pathogen. No bacteria, no virus.” He shrugged. “Let’s take several potatoes.”

They went out and dug potatoes from the field. Some of them were gnarled, elongated, cracked. “What is it?” Nirgal exclaimed.

Sax was frowning a little. “Looks like spindle tuber disease.”

“What causes it?”

“A viroid.”

“What’s that?”

“A bare RNA fragment. Smallest known infectious agent. Strange.”

“Ka.” Nirgal felt his stomach clamping inward. “How did it get here?”

“On a parasite, probably. This kind seems to be infecting grass. We need to find out.”

So they gathered samples, and drove back down to Sabishii.

Nirgal sat on a futon on the floor of Tariki’s living room, feeling sick. Tariki and Sax talked long after dinner, discussing the situation. Other viroids had been appearing in a rapid dispersal from Tharsis; apparently they had made it across the cordon sanitaire of space, arriving on a world that had been previously innocent of them. They were smaller than viruses, much smaller, and quite a bit simpler. Nothing but strands of RNA, Tariki said, about fifty nanometers long. Individuals had a molecular weight of about 130,000, while the smallest known viruses had molecular weights of over a million. They were so small that they had to be centrifuged at over 100,000 g in order to be pulled out of suspension.

The potato-spindle-tuber viroid was well understood, Tariki told them, tapping around on his screen and pointing at the schematics called up. A chain of merely 359 nucleotides, lined out in a closed single strand with short double-strand regions braiding it. Viroids like this one caused several plant diseases, including pale cucumber disease, chrysanthemum stunt, chlorotic mottle, cadang-cadang, citrus exocortis. Viroids had also been confirmed as the agent in some animal brain diseases, like scrapie, and kuru, and Creutzfeldt-Jakob disease in humans. The viroids used host enzymes to reproduce, and then were taken to be regulatory molecules in the nuclei of infected cells, disturbing growth-hormone production in particular.

The particular viroid in Nirgal’s basin, Tariki said, had mutated from potato spindle tuber. They were still identifying it in the labs at the university, but the sick grass made him sure they were going to find something different, something new.

Nirgal felt sick. The names of the diseases alone were enough to do it. He stared at his hands, which had been plunged thick in infected plants. Through the skin, into the brain, some kind of spongiform encephalopathy, mushroom growths of brain blooming everywhere.

“Is there anything we can do to fight it?” he said.

Sax and Tariki looked at him.

“First,” Sax said, “we have to find out what it is.”

• • •

That turned out to be no simple matter. After a few days, Nirgal returned to his basin. There he could at least do something; Sax had suggested removing all the potatoes from the potato fields. This was a long dirty task, a kind of negative treasure hunt, as he turned up diseased tuber after tuber. Presumably the soil itself would still hold the viroid. It was possible he would have to abandon the field, or even the basin. At best, plant something else. No one yet understood how viroids reproduced; and the word from Sabishii was that this might not even be a viroid as previously understood.

“It’s a shorter strand than usual,” Sax said. “Either a new viroid, or something like a viroid but smaller still.” In the Sabishii labs they were calling it “the virid.”

A long week later, Sax came back up to the basin. “We can try to remove it physically,” he said over dinner. “Then plant different species, ones that are resistant to viroids. That’s the best we can do.”

“But will that work?”

“The plants susceptible to infection are fairly specific. You got hit by a new one, but if you change grasses, and types of potatoes— perhaps cycle out some of your potato-patch soil. . . .” Sax shrugged.

Nirgal ate with more appetite than he had had for the previous week. Even the suggestion of a possible solution was a great relief. He drank some wine, felt better and better. “These things are strange, eh?” he said over an after-dinner brandy. “What life will come up with!”

“If you call it life.”

“Well, of course.”

Sax didn’t reply.

“I’ve been looking at the news on the net,” Nirgal said. “There are a lot of infestations. I had never noticed before. Parasites, viruses. . . .”

“Yes. Sometimes I worry about a global plague. Something we can’t stop.”

“Ka! Could that happen?”

“There’s all kinds of invasions going on. Population surges, sudden die-offs. All over. Things in disequilibrium. Upsetting balances we didn’t even know existed. Things we don’t understand.” As always this thought made Sax unhappy.

“Biomes will eventually come into equilibrium,” Nirgal suggested.

“I’m not sure there is such a thing.”

“As equilibrium?”

“Yes. It may be a matter of. . . .” He waved his hands about like gulls. “Punctuated equilibrium, without the equilibrium.”

“Punctuated change?”

“Perpetual change. Braided change— sometimes surging change—”

“Like cascading recombinance?”

“Perhaps.”

“I’ve heard that’s a mathematics only a dozen people can really understand.”

Sax looked surprised. “That’s never true. Or else, true of every math. Depends on what you mean by understand. But I know a bit of that one. You can use it to model some of this stuff. But not predict. And I don’t know how to use it to suggest any— reactions on our part. I’m not sure it can be used that way.” He talked for a while about Vlad’s notion of holons, which were organic units that had subunits and also were subunits of greater holons, each level combining to create the next one up in emergent fashion, all the way up and down the great chain of being. Vlad had worked out mathematical descriptions of these emergences, which turned out to come in more than one kind, with different families of properties for each kind; so if they could get enough information about the behavior of a level of holons and the next level up, they could try to fit them into these mathematical formulae, and see what kind of emergence they had; then perhaps find ways to disrupt it. “That’s the best approach we can take for things this little.”

The next day they called up greenhouses in Xanthe, to ask for shipments of new starts, and flats of a new strain of Himalayan-based grass. By the time they arrived, Nirgal had pulled out all the grass in the basin, and much of the moss. The work made him sick, he couldn’t help it; once, seeing a concerned marmot patriarch chattering at him, he sat down and burst into tears. Sax had retreated into his customary silence, which only made things worse, as it always reminded Nirgal of Simon, and of death generally. He needed Maya or some other courageous expressive speaker of the inner life, of anguish and fortitude; but here was Sax, lost in thoughts that seemed to happen in some kind of foreign language, in a private idiolect he was now unwilling to translate.

They went to work planting new starts of Himalayan grasses throughout the basin, concentrating on the stream banks and their veinlike tracery under the trickles and ice. A hard freeze actually helped, as it killed the infected plants faster than the ones free of infection. They incinerated the infected plants in a kiln down the massif. People came from the surrounding basins to help, bringing replacement starts for planting later.

Two months passed, and the invasion surge weakened. The plants that remained seemed to be more resistant. Newly planted plants did not get infected or die. The basin looked like it was autumn, though it was midsummer; but the dying had stopped. The marmots looked thin, and more concerned than ever; they were a worrying species. And Nirgal could see their point. The basin looked ravaged. But it seemed the biome would survive. The viroid was subsiding, eventually they could hardly even find it, no matter how hard and long they centrifuged samples. It seemed to have left the basin, as mysterious in departure as in arrival.

Sax shook his head. “If the viroids that infect animals ever get more robust. . . .” He sighed. “I wish I could talk to Hiroko about it.”

“I’ve heard them say she’s at the north pole,” Nirgal said sourly.

“Yes.”

“But?”

“I don’t think she’s there. And— I don’t think she wants to talk to me. But I’m still . . . I’m waiting.”

“For her to call?” Nirgal said sarcastically.

Sax nodded.

They stared into Nirgal’s lamp flame glumly. Hiroko— mother, lover— she had abandoned them both.

But the basin would live. When Sax went to his rover to leave, Nirgal gave him a bear hug, lifting him and twirling him. “Thanks.”

“My pleasure,” Sax said. “Very interesting.”

“What will you do now?”

“I think I will talk to Ann. Try to talk to Ann.”

“Ah! Good luck.”

Sax nodded, as if to say he would need it. Then he drove off, waving once before putting both hands on the wheel. In a minute he was over the rib and gone.

• • •

So Nirgal went at the hard work of restoring the basin, doing what he could to give it more pathogen resistance. More diversity, more of an indigenous parasite load. From the chasmoendolithic rock dwellers to the insects and microbial fliers hovering in the air. A fuller, tougher biome. He seldom went into Sabishii. He replaced all the soil in the potato patch, planted a different kind of potato.

Sax and Spencer had come back to visit him, when a big dust storm began in the Claritas region near Senzeni Na— at their latitude, but all the way around the world. They heard about it over the news, and then tracked it over the next couple of days on the satellite weather photos. It came east, kept coming east; kept coming; looked like it was going to pass to the south of them; but at the last minute it veered north.

They sat in the living room of his boulder house looking south. And there it came, a dark mass filling the sky. Dread filled Nirgal like the static electricity causing Spencer to yelp when he touched things. The dread didn’t make sense, they had passed under a score of dust storms before. It was only residual dread from the viroid blight. And they had weathered that.

But this time the light of day browned and dimmed until it might as well have been night— a chocolate night, howling over the boulder and rattling the outer window. “The winds have gotten so strong,” Sax remarked pensively. Then the howl lessened, while it was still dark out. Nirgal felt more and more sick the less the wind howled— until the air was still, and he was so nauseated he could scarcely stand at the window. Global dust storms sometimes did this; they ended abruptly when the wind ran into a counterwind, or a particular landform. And then the storm dropped its load of dust and fines. It was raining dust now, in fact, the boulder’s windows a dirty gray. As if ash were settling over the world. In the old days, Sax was muttering uneasily, even the biggest dust storms would only have dropped a few millimeters of fines at the end of their runs. But with the atmosphere so much thicker, and the winds so much more powerful, great quantities of dust and sand were thrown aloft; and if they came down all at once, as sometimes happened, the drifts could be much deeper than a few millimeters.

As near suspension as some fines were, in an hour all but the very finest had fallen out of the air and onto them. After that it was only a hazy afternoon, windless, the air filled with something like a thin smoke, so that they could see the whole of the basin; which was covered with a lumpy blanket of dust.

Nirgal went out with his mask on as always, and dug desperately with a shovel, then with his bare hands. Sax came out, staggering through the soft drifts, to put a hand to Nirgal’s shoulder. “I don’t believe there’s anything that can be done.” The layer of dust was about a meter deep, or deeper.

In time, other winds would blow some of this dust away. Snow would fall on the rest of it, and when the snow melted, the resulting mud would run over the spillways, and a new leaf-vein system of channels would cut a new fractal pattern, much like the old one. Water would carry the dust and fines away, down the massif and into the world. But by the time that happened, every plant and animal in the basin would be dead.