The white stair winds downward for quite some while. The tunnel walls are close and claustrophobic, but the air somehow isn’t stale. Just being free of the ashfall is novelty enough, but Nassun notices that there’s not much dust, either. That’s weird, isn’t it? All of this is weird.

“Why isn’t there dust?” Nassun asks as they walk. She speaks in hushed tones at first, but gradually she relaxes – a little. It’s still a deadciv ruin, after all, and she’s heard lots of lorist tales about how dangerous such places can be. “Why do the lights still work? That door we came through back there, why did it still work?”

“I haven’t a clue, little one.” Schaffa now precedes her down the steps, on the theory that anything dangerous should encounter him first. Nassun can’t see his face, and must gauge his mood by his broad shoulders. (It bothers her that she does this, watching him constantly for shifts of mood or warnings of tension. It is another thing she learned from Jija. She cannot seem to shed it with Schaffa, or anyone else.) He’s tired, she can see, but otherwise well. Satisfied, perhaps, that they have made it here. Wary, of what they might find – but that makes two of them. “With deadciv ruins, sometimes the answer is simply ‘because.’”

“Do you… remember anything, Schaffa?”

A shrug, not as nonchalant as it should be. “Some. Flashes. The why, rather than the what.”

“Then, why? Why do Guardians come here, during a Season? Why don’t they just stay wherever they are, and help the comms they join the way you helped Jekity?”

The stairs are ever so slightly too wide for Nassun’s stride, even when she keeps to the more narrow inner bend. Periodically she has to stop and put both feet on one step in order to rest, then trot to catch up. He is drumbeat-steady, proceeding without her – but abruptly, just as she asks these questions, they reach a landing within the stairwell. To Nassun’s great relief, Schaffa stops at last, signaling that they can sit down and rest. She’s still soaked with sweat from the frantic scrabble through the grass forest, though it has begun to dry now that she’s moving slower. The first drink of water from her canteen is sweet, and the floor feels comfortingly cool, though hard. She’s abruptly sleepy. Well, it is night outside, up on the surface where grasshoppers or cicadas now cavort.

Schaffa rummages in his pack and hands her a slab of dried meat. She sighs and begins the laborious process of gnawing on it. He smiles at her grumpiness, and perhaps to soothe her, he finally answers her question.

“We leave during Seasons because we have nothing to offer to a comm, little one. I cannot have children, for one thing, which makes me a less than ideal community adoptee. However much I might contribute toward the survival of any comm, its investment in me will return only short-term gains.” He shrugs. “And without orogenes to tend, over time, we Guardians become… difficult to live with.”

Because the things in their heads make them want magic all the time, she realizes. And although orogenes make enough of the silver to spare, stills don’t. What happens when a Guardian takes silver from a still? Maybe that’s why Guardians leave – so no one will find out.

“How do you know you can’t have children?” she presses. This is maybe too personal a question, but he has never minded her asking those. “Did you ever try?”

He’s taking a drink from his canteen. When he lowers it, he looks bemused. “It would be clearer to say that I should not,” he says. “Guardians carry the trait of orogeny.”

“Oh.” Schaffa’s mother or father must have been an orogene! Or maybe his grandparents? Anyway, the orogeny didn’t come out in him the way it has in Nassun. His mother – she decides arbitrarily that it was his mother, for no particular reason – never needed to train him, or teach him to lie, or break his hand. “Lucky,” she murmurs.

He’s in the middle of raising the canteen again when he pauses. Something flows over his face. She’s learned to read this look of his in particular, despite the fact that it’s such a rare one. Sometimes he’s forgotten things he wishes he could remember, but right now, he is remembering what he wishes he could forget.

“Not so lucky.” He touches the nape of his neck. The bright, nerve-etched network of searing light within him is still active – hurting him, driving at him, trying to break him. At the center of that web is the shard of corestone that someone put into him. For the first time, Nassun wonders how it was put into him. She thinks about the long, ugly scar down the back of his neck, which she thinks he keeps his hair long to cover. She shivers a little with the implications of that scar.

“I don’t —” Nassun tries to drag her thoughts away from the image of Schaffa screaming while someone cuts him. “I don’t understand Guardians. The other kind of Guardian, I mean. I don’t… They’re awful.” And she cannot even begin to imagine Schaffa being like them.

He doesn’t reply for a while, as they chew through their meal. Then, softly, he says, “The details are lost to me, and the names, and most of the faces. But the feelings remain, Nassun. I remember that I loved the orogenes to whom I was Guardian – or at least, I believed that I loved them. I wanted them to be safe, even if that meant inflicting small cruelties to hold the greater at bay. Anything, I felt, was better than genocide.”

Nassun frowns. “What’s genocide?”

He smiles again, but it is sad. “If every orogene is hunted down and slain, and if the neck of every orogene infant born thereafter is wrung, and if every one like me who carries the trait is killed or effectively sterilized, and if even the notion that orogenes are human is denied… that would be genocide. Killing a people, down to the very idea of them as a people.”

“Oh.” Nassun feels queasy again, inexplicably. “But that’s…”

Schaffa inclines his head, acknowledging her unspoken But that’s what’s been happening. “This is the task of the Guardians, little one. We prevent orogeny from disappearing – because in truth, the people of the world would not survive without it. Orogenes are essential. And yet because you are essential, you cannot be permitted to have a choice in the matter. You must be tools – and tools cannot be people. Guardians keep the tool… and to the degree possible, while still retaining the tool’s usefulness, kill the person.”

Nassun stares back at him, understanding shifting within her like an out-of-nowhere niner. It is the way of the world, but it isn’t. The things that happen to orogenes don’t just happen. They’ve been made to happen, by the Guardians, after years and years of work on their part. Maybe they whispered ideas into the ears of every warlord or Leader, in the time before Sanze. Maybe they were even there during the Shattering – inserting themselves into ragged, frightened pockets of survivors to tell them who to blame for their misery, and how to find them, and what to do with the culprits found.

Everybody thinks orogenes are so scary and powerful, and they are. Nassun is pretty sure she could wipe out the Antarctics if she really wanted, though she would probably need the sapphire to do it without dying. But despite all her power, she’s still just a little girl. She has to eat and sleep like every other little girl, among people if she hopes to keep eating and sleeping. People need other people to live. And if she has to fight to live, against every person in every comm? Against every song and every story and history and the Guardians and the militia and Imperial law and stonelore itself? Against a father who could not reconcile daughter with rogga? Against her own despair when she contemplates the gargantuan task of simply trying to be happy?

What can orogeny do against something like that? Keep her breathing, maybe. But breathing doesn’t always mean living, and maybe… maybe genocide doesn’t always leave bodies.

And now she is more certain than ever that Steel was right.

She looks up at Schaffa. “Till the world burns.” It’s what he said to her, when she told him what she meant to do with the Obelisk Gate.

Schaffa blinks, then smiles the tender, awful smile of a man who has always known that love and cruelty are two faces of the same coin. He pulls her close and kisses her forehead, and she hugs him tight, so very glad to have one parent, at last, who loves her as he should.

“Till the world burns, little one,” he murmurs against her hair. “Of course.”

***

In the morning, they resume walking down the winding stair.

The first sign of change is the appearance of another railing on the other side of the stairwell. The railing itself is made of strange stuff, bright gleaming metal not marred at all by verdigris or tarnish. Now, though, there are twin railings, and the stairwell widens enough that two people can walk abreast. Then the winding stairwell begins to unwind – still descending at the same angle, but less and less curved, until finally it extends straight ahead, into darkness.

After an hour or so of walking, the tunnel suddenly opens out, walls and roof vanishing. Now they descend along a trail of lighted, linked stairs that are completely unsupported, somehow, in open air. The stairs should not be possible, held up as they are by nothing but the railing and, apparently, each other – but there is no judder or creak as Nassun and Schaffa walk down. Whatever the stuff that comprises the steps is, it’s much stronger than ordinary stone.

And now they’re descending into a massive cavern. It’s impossible to see how large it is in the darkness, although shafts of illumination slant down from occasional circles of cool white light that dot the cavern’s ceiling at irregular intervals. The light illuminates… nothing. The cavern’s floor is a vast expanse of empty space filled with irregular, lumpen piles of sand. But now that they are within what Nassun once thought was an empty magma chamber, she can sess things more clearly, and all at once she realizes just how wrong she was.

“This isn’t a magma chamber,” she tells Schaffa in an awed tone. “It wasn’t a cavern at all when this city was built.”

“What?”

She shakes her head. “It wasn’t enclosed. It must have been… I don’t know? Whatever’s left when a volcano blows up completely.”

“A crater?”

She nods quickly, excited with the realization. “It was open to the sky then. People built the city in the crater. But then there was another eruption, right in the middle of the city.” She points ahead of them, into the dark; the stairwell is going right toward what she sesses is the epicenter of this ancient destruction.

But that can’t be right. Another eruption, depending on the type of lava, should simply have destroyed the city and filled the old crater. Instead, somehow, all the lava went up and over the city, spreading out like a canopy and solidifying over it to form this cavern. Leaving the city within the crater more or less intact.

“Impossible,” Schaffa says, frowning. “Not even the most viscous lava would behave that way. But…” His expression clouds. Again he is trying to sift through memories truncated and trimmed, or perhaps simply dimmed by age. On impulse Nassun grabs his hand, to encourage him. He glances at her, smiles absently, and resumes frowning. “But I think… an orogene could do such a thing. It would take one of rare power, however, and probably the aid of an obelisk. A ten-ringer. At least.”

Nassun frowns in confusion at this. The gist of what he’s said fits, though: Someone did this. Nassun looks up at the ceiling of the cavern and realizes belatedly that what she thought were odd stalactites are actually – she gasps – the leftover impressions of buildings that are no longer there! Yes, there is a narrowing point that must have been a spire; here a curving arch; there a geometric strangeness of spokes and curves that looks oddly organic, like the under-ribs of a mushroom cap. But while these imprints fossil all over the ceiling of the cavern, the solidified lava itself stops a few hundred feet above the ground. Belatedly, Nassun realizes that the “tunnel” from which they emerged is also the remains of a building. Looking back, she sees that the outside of the tunnel looks like one of the cuttlebones that her father once used for fine knapping work – more solid, and made from the same strange white material as the slab up on the surface. That must have been the top of the building. But a few feet below where the canopy ends, the building does, too, to be replaced by this strange white stair. That must have been done sometime after the disaster – but how? And by whom? And why?

Trying to understand what she’s seeing, Nassun looks more closely at the cavern’s floor. The sand is mostly pale, though there are mottling patches of darker gray and brown laced throughout. In a few places, twisted lengths of metal or immense broken fragments of something larger – other buildings, maybe – poke through the sand like bones from a half-unearthed grave.

But this is wrong, too, Nassun realizes. There isn’t enough material here to be the remnants of a city. She hasn’t seen many deadciv ruins, or cities for that matter, but she’s read about them and heard stories. She’s pretty sure that cities are supposed to be full of stone buildings and wooden storecaches and maybe metal gates and cobbled streets. This city is nothing, relatively speaking. Just metal and sand.

Nassun puts down her hands, which she’s raised without thinking while her fleshless senses flicker and search. Inadvertently she glances down, which makes the distance between the stair she stands on and that sandy cavern floor yawn and seem to stretch. This makes her step back closer to Schaffa, who puts a reassuring hand on her shoulder.

“This city,” Schaffa says. She glances at him in surprise; he looks thoughtful. “There is a word in my mind, but I don’t know what it is. A name? Something that holds meaning in another language?” He shakes his head. “But if this is the city I think it is, I have heard tales of its grandeur. Once, they say, this city held billions of people.”

That seems impossible. “In one city? How big was Yumenes?”

“A few million.” He smiles at her openmouthed gape, then sobers somewhat. “And now there can’t be many more people than that, altogether, across the whole of the Stillness. When we lost the Equatorials, we lost the bulk of humanity. Still. Once, the world was even bigger.”

It can’t be. The volcanic crater is only so vast. And yet… Delicately, Nassun sesses below the sand and debris, searching for evidence of the impossible. The sand is much deeper than she thought. Far beneath its surface, though, she finds pressed pathways in long, straight lines. Roads? Foundations, too, though they are in oblong and round and other odd shapes: hourglass loops and fat S-curves and bowl-shaped dips. Not a single square. She puzzles over the odd composition of these foundations, and then abruptly realizes that it all has the sess of something mineralized, alkaline. Oh, it’s petrifying! Which means that originally – Nassun gasps.

“It’s wood,” she blurts aloud. A building foundation of wood? No, it’s something like wood, but also a bit like the polymer stuff that her father used to make, and a little like the strange not-stone of the stair they’re standing on. All the roads she can sess are something similar. “Dust. Everything down there, Schaffa. It’s not sand, it’s dust! It’s plants, lots of them, dead so long ago that it’s all just dried up and crumbled away. And…” Her gaze is drawn back up to the lava canopy overheard. What must it have been like? The whole cavern lit up in red. The air too hot to breathe. The buildings lasted longer, long enough for the lava to start to cool around them, but every person in this city would have roasted within the first few hours of being buried under a bubble of fire.

That’s what’s in the sand, too, then: countless people, cooked into char and crumbled away.

“Intriguing,” Schaffa says. He leans on the railing, heedless of the distance to the ground as he gazes out over the cavern. Nassun’s belly clenches in fear for him. “A city built of plants.” Then his gaze sharpens. “But nothing’s growing here now.”

Yes. That’s the other thing Nassun has noticed. She’s traveled enough now, and seen enough other caves to know that this place should be teeming with life, like lichens and bats and blind white insects. She shunts her perception into the realm of the silver, searching for the delicate lines that should be everywhere amid so much living detritus. She finds them, lots of them, but… Something is strange. The lines flow together and focus, tiny threads becoming thicker channels – much like the way magic flows within an orogene. She’s never seen this happen in plants or animals or soil before. These more concentrated flows come together and continue forward – the direction in which the stairway is going. She follows them well past the stairway she can see, thickening, brightening… and then somewhere ahead, they abruptly stop.

“Something bad is here,” Nassun says, her skin prickling. Abruptly she stops sessing. She does not want to sess what’s ahead, for some reason.

“Nassun?”

“Something is eating this place.” She blurts the words, then wonders why she’s said them. But now that she’s said it, she feels like it was the right thing to say. “That’s why nothing grows. Something is taking all the magic away. Without that, everything’s dead.”

Schaffa regards her for a long moment. One of his hands, Nassun sees, is on the hilt of his black glass poniard, where it’s strapped against his thigh. She wants to laugh at this. What’s ahead isn’t something he can stab. She doesn’t laugh because it’s cruel, and because she’s suddenly so scared that if she starts laughing, she might not stop.

“We don’t have to go forward,” Schaffa suggests. It is gentle, and badly needed reassurance that he will not lose respect for her if she abandons her mission out of fear.

It bothers Nassun, though. She has her pride. “N-no. Let’s keep going.” She swallows hard. “Please.”

“Very well, then.”

They proceed. Someone or something has dug a channel through the dust, beneath and around the impossible stair. As they continue to descend, they pass mountains of the stuff. Presently, though, Nassun sees another tunnel looming ahead. This one is set against the floor of the cavern – at last – and its mouth is immense. Concentric arches, each carved from marble in different shades, loom high overhead as the stairway finally reaches the ground and flattens into the surrounding stones. The tunnel narrows further in; there’s only darkness beyond. The floor of the entryway is something that looks like lacquer, tiled in gradient shades of blue and black and dark red. It is rich and lovely color, a relief to the eyes after so much white and gray, and yet it, too, is impossibly strange. Somehow, none of the city’s dust has blown or subsided into this entryway.

Dozens of people could pass through that archway. Hundreds in a minute. Now, however, only one stands here, watching them from under a band of rose marble that contrasts sharply against his paler, colorless lines. Steel.

He doesn’t move as Nassun walks over to him. (Schaffa comes over, too, but he is slower, tense.) Steel’s gray gaze is fixed on an object beside him that is not familiar to Nassun but which would be to her mother: a hexagonal plinth rising from the floor, like a smoky quartz crystal shaft that has been sheared off halfway. Its topmost surface is at a slight angle. Steel’s hand is held toward it in a gesture of presentation. For you.

So Nassun focuses on the plinth. She reaches toward it and jerks back as something lights up around its rim before her fingers can touch the slanted surface. Bright red marks float in the air above the crystal, etching symbols into empty space. She cannot fathom their meaning, but the color unnerves her. She looks up at Steel, who has not moved and looks as if he’s been in the same position since this place was built. “What does it say?”

“That the transport vehicle I told you about is currently nonfunctional,” says the voice from within Steel’s chest. “You’ll need to power and reboot the system before we can use this station.”

“‘R-re… boot?’” She tries to figure out what putting on boots has to do with ancient ruins, then decides to run with the part she understands. “How do I give it power?”

Abruptly, Steel is in a different position, facing the archway that leads deeper into the station. “Go inside and provide power at the root. I’ll stay here and key in the start-up sequence once there’s enough power.”

“What? I don’t —”

His gray-on-gray eyes shift over to her. “You’ll see what to do inside.”

Nassun chews on the inside of her cheek, looking into the archway. It’s really dark in there.

Schaffa’s hand touches her shoulder. “I’ll go with you, of course.”

Of course. Nassun swallows and nods, grateful. Then she and Schaffa walk into the dark.

It doesn’t stay dark for long. Like on the white stair, small panels of light begin glowing along the sides of the tunnel as they progress. The lights are dim, and yellowy in a way that suggests age, weathering, or… well, or weariness. That’s the word that pops into Nassun’s head for some reason. The light is enough to glimmer off the edges of the tiles beneath their feet. There are doors and alcoves along the tunnel walls, and at one point Nassun spots a strange contraption jutting out about ten feet up. It looks like… a wagon bed? Without wheels or a yoke, and as if that wagon bed was made of the same smooth material as the stair, and as if that wagon bed ran along some kind of track set into the wall. It seems obviously made to transport people; maybe it’s how people who couldn’t or wouldn’t walk got around? Now it is still and dark, locked to the wall forever where its last driver left it.

They notice the peculiar bluish light illuminating the tunnel up ahead, but that still isn’t adequate warning enough to prepare them for when the path suddenly curves left, and they find themselves in a new cavern. This much smaller cavern isn’t full of dust, or at least not much of it. What it does contain, instead, is a titanic column of solid blue-black volcanic glass.

The column is huge, and irregular, and impossible. Nassun just stares, openmouthed, at this thing that fills nearly the whole cavern, ground to ceiling and beyond. That it is the solidified, rapidly cooled product of what must have been a titanic explosion is immediately obvious. That it is somehow the source of the lava canopy which flowed into the adjoining cavern is equally indisputable.

“I see,” Schaffa says. Even he sounds overwhelmed, his voice softened by awe. “Look.” He points down. This is what finally provides Nassun the focal point to establish perspective, and size, and distance. The thing is huge, because now she can see tiers that descend toward its base, ringing it in concentric octagons. Three of them. On the outermost tier are buildings, she thinks. They’re badly damaged, half fallen in, just shells, but she sesses at once why they still exist where the ones in the cavern beyond have crumbled. The heat that must have filled this cavern has metamorphized something in the buildings’ construction, hardening and preserving them. Some sort of concussion has done damage, too: All the buildings are torn open on the same side, facing the great glass column. Looking from what she guesses is a three-story building to the glass column, she guesstimates that the column is not as far away as it looks; it’s just much bigger than she initially guessed. The size of… oh.

“An obelisk,” she whispers. And then she can sess and guess what happened, as clearly as if she were there.

Long ago, an obelisk sat here, at the bottom of this cavern, one of its points jammed into the ground like some kind of bizarre plant. At some point, the obelisk lifted free of the pit, to float and shimmer like its fellows above the strange immensity of the city – and then something went very, very wrong. The obelisk… fell. Where it struck the earth, Nassun imagines she can hear the echo of the concussion; it did not merely fall, it drove its way in, punching through and churning down and down and down, powered by all the force of concentrated silver within its core. Nassun can’t track its path for more than a mile or so down, but there’s no reason to think it didn’t just keep going. To where, she cannot guess.

And in its wake, channeled straight up from the most molten part of the earth, came a literal fountain of earthfire to bury this city.

There’s still nothing around that looks like a way to supply power to the station. Nassun notices, though, that the cavern’s illumination comes from enormous pylons of blue light near the base of the glass column. These make up the lower- and innermost tier of the chamber. Something is making that light.

Schaffa, too, has come to the same conclusion. “The tunnel ends here,” he says, gesturing toward the blue pylons and the column’s base. “There’s nowhere else to go but to the foot of this monstrosity. But are you certain you want to follow in the footsteps of whoever did this?”

Nassun bites her bottom lip. She does not. Here is the wrongness that she sessed from the stair, though she cannot tell its source yet. Still… “Steel wants me to see whatever is down there.”

“Are you certain you want to do what he wishes, Nassun?”

She isn’t. Steel cannot be trusted. But she’s already committed herself to the path of destroying the world; whatever Steel wants cannot be worse than this. So when Nassun nods, Schaffa simply inclines his head in acquiescence, and offers her his hand so that they can walk down the road to the pylons together.

Walking past the tiers feels like moving through a graveyard, and Nassun feels compelled to a respectful silence for that reason. Between the buildings, she can make out carbonized walkways, melted-glass troughs that must have once held plants, strange posts and structures whose purpose she isn’t sure she’d be able to fathom even if they weren’t half-melted. She decides that this post is for tying horses, and that frame is where the tanners racked drying hides. Remapping the familiar onto the strange doesn’t work very well, of course, because nothing about this city is normal. If the people who lived here rode mounts, they were not horses. If they made pottery or tools, those were not shaped from clay or obsidian, and the crafters who made such things were not merely knappers. These are people who built, and then lost control of, an obelisk. There is no telling what wonders and horrors filled their streets.

In her anxiety, Nassun reaches up to touch the sapphire, mostly just to reassure herself that she can do so through tons of cooled lava and petrifying decayed city. It is as easy to connect to here as it was up there, which is a relief. It tugs at her gently – or as gently as any obelisk does – and for a moment she lets herself be drawn into its flowing, watery light. It does not frighten her to be so drawn in; to the degree that one can trust an inanimate object, Nassun trusts the sapphire obelisk. It is the thing that told her about Corepoint, after all, and now she senses another message in the shimmering interstices of its tight-packed lines —

“Up ahead,” she blurts, startling herself.

Schaffa stops and looks at her. “What?”

Nassun has to shake her head, drawing her mind back into itself and out of all that blue. “The… the place to put in power. Is up ahead, like Steel said. Past the track.”

“Track?” Schaffa turns, gazing down the sloping walkway. Up ahead is the second tier – a smooth, featureless plane of more of that not-stone white stuff. The people who built the obelisks seem to have used that stuff in all their oldest and most enduring ruins.

“The sapphire… knows this place,” she tries to explain. It’s a fumbling sort of explanation, as hard as trying to describe orogeny to a still. “Not this place specifically, but somewhere like it…” She reaches for it again, asking for more without words, and is nearly overwhelmed with a blue flicker of images, sensations, beliefs. Her perspective changes. She stands at the center of three tiers, no longer in a cavern but facing a blue horizon across which pleasant clouds churn and race and vanish and are reborn. The tiers around her teem with activity – though it all blurs together, and what she can discern of the few instants of stillness makes no sense. Strange vehicles like the car she saw in the tunnel run along the sides of buildings, following tracks of differently colored light. The buildings are covered in green, vines and grassy rooftops and flowers curling over lintels and walls. People, hundreds of them, go in and out of these, and walk up and down the paths in unbroken blurs of motion. She cannot see their faces, but she catches glimpses of black hair like Schaffa’s, earrings of artfully curled vine motifs, a dress swirling about ankles, fingers flicking while adorned with sheaths of colored lacquer.

And everywhere, everywhere, is the silver that lies beneath heat and motion, the stuff of the obelisks. It spiders and flows, converging not just into trickles but rivers, and when she looks down she sees that she stands in a pool of liquid silver, soaking in through her feet —

Nassun staggers a little as she comes back this time, and Schaffa’s hand lands firmly on her shoulder to steady her. “Nassun.”

“I’m all right,” she says. She isn’t sure of that, but she says it anyway because she doesn’t want him to worry. And because it is easier to say this than I think I was an obelisk for a minute.

Schaffa moves around to crouch in front of her, gripping her shoulders. The concern in his expression almost, almost, eclipses the weary lines, the hint of distraction, and the other signs of struggle that are building beneath the surface of him. His pain is worse, here underground. He hasn’t said that it is, and Nassun doesn’t know why it’s getting worse, but she can tell.

But. “Don’t trust the obelisks, little one,” he says. This does not seem nearly as strange or wrong a thing for him to say as it should. On impulse Nassun hugs Schaffa; he holds her tight, rubbing comfort into her back. “We allowed a few to progress,” he murmurs in her ear. Nassun blinks, remembering poor, mad, murderous Nida, who said the same thing once. “Back in the Fulcrum. I was permitted to remember that much because it’s important. The few who reached ninth- or tenth-ring status… they were always able to sense the obelisks, and the obelisks could sense them in turn. They would have drawn you to them one way or another. They’re missing something, incomplete somehow, and that’s what they need an orogene to provide.

“But the obelisks killed them, my Nassun.” He presses his face into her hair. She’s filthy and hasn’t truly washed since Jekity, but his words strip away such mundane thoughts. “The obelisks… I remember. They will change you, remake you, if they can. That’s what that rusting stone eater wants.”

His arms tighten for an instant, with a hint of his old strength, and it is the most beautiful feeling in the world. She knows in this moment that he will never falter, never not be there when she needs him, never devolve into a mere fallible human being. And she loves him more than life for his strength.

“Yes, Schaffa,” she promises. “I’ll be careful. I won’t let them win.”

Him, she thinks, and she knows he thinks it too. She won’t let Steel win. At least not without getting what she wants first.

So they are resolved. When Nassun pulls back, Schaffa nods before getting to his feet. They go forward again.

The innermost tier sits in the glass column’s blue, gloomy shadow. The pylons are bigger than they looked from afar – perhaps twice as tall as Schaffa, three or four times as wide, and humming faintly now that Nassun and Schaffa are close enough to hear. They’re arranged in a ring around what must have once been the resting place of an obelisk, like a buffer protecting the outer two tiers. Like a fence, separating the bustling life of the city from… this.

This: At first Nassun thinks it is a thicket of thorns. The thornvines curl and tangle along the ground and up the inner surface of the pylons, filling all the available space between them and the glass column itself. Then she sees that they aren’t thornvines: no leaves. No thorns. Just these curling, gnarling, ropelike twists of something that looks woody but smells a little like fungus.

“How odd,” Schaffa says. “Something alive at last?”

“M-maybe they aren’t alive?” They do look dead, though they stand out by being still recognizably plants and not crumbled bits of decay on the ground. Nassun does not like it here, amid these ugly vines and in the shadow of the glass column. Is that what the pylons are for, to cut off sight of the vines’ grotesquerie from the rest of the city? “And maybe they grew here after… the rest.”

Then she blinks, noticing something new about the vine nearest her. It’s different from the others around it. Those are obviously dead, withered and blackened and broken off in places. This one, however, looks as though it might be alive. It is ropy and knotted in places, with a wood-like surface that looks old and rough, but whole. Debris litters the floor beneath it – grayish lumps and dust, scraps of dry-rotted cloth, and even a moldering length of frayed rope.

There is a thing Nassun has resisted doing since entering the cavern of the glass column; some things she doesn’t quite want to know. Now, however, she closes her eyes and reaches inside the vine with her sense of the silver.

At first it’s hard. The cells of the thing – because it is alive, more like a fungus than a plant, but there is also something artificial and mechanical about the way it has been made to function – press together so tightly that she doesn’t expect to see any silver between them. More dense than the stuff in people’s bodies. The arrangement of its substance is almost crystalline, in fact, cells lined up in neat little matrices, which she’s never seen in a living thing before.

And now that Nassun has seen down into the interstices of the vine’s substance, she can see that it doesn’t have any silver in it. What it has instead are… She isn’t sure how to describe it. Negative spaces? Where silver should be, but isn’t. Spaces that can be filled with silver. And as she gingerly explores them, fascinated, she begins to notice the way they pull at her perception, more and more, until – with a gasp, Nassun jerks her perception free.

You’ll see what to do, Steel has said. It should be obvious.

Schaffa, who has crouched to peer at the bit of rope, pauses and glances at her, frowning. “What is it?”

She stares back at him, but she doesn’t have the words to say what needs to be done. The words do not exist. She knows, however, what she needs to do. Nassun takes a step closer to the living vine.

“Nassun,” Schaffa says, his voice tight and warning with sudden alarm.

“I have to, Schaffa,” she says. She’s already lifting her hands. This is where all the silver of the outer cavern has been going, she realizes now; these vines have been eating it up. Why? She knows why, in the deepest and most ancient design of her flesh. “I have to, um, power the system.”

Then, before Schaffa can stop her, Nassun wraps both hands around the vine.

It does not hurt. That’s the trap of it. The sensation that spreads throughout her body is pleasant, in fact. Relaxing. If she could not perceive the silver, or the way the vine instantly starts dragging every bit of silver out of the spaces between her cells, she would think it was doing something good for her. As it is, it will kill her in moments.

She has access to more silver than just her own, though. Lazily, through the languor, Nassun reaches for the sapphire – and the sapphire responds instantly, easily.

Amplifiers, Alabaster called them, long before Nassun was ever born. Batteries is how you think of them, and how you once explained them to Ykka.

What Nassun understands the obelisks to be is simply engines. She’s seen engines at work – the simple pump-and-turbine things that regulated geo and hydro back in Tirimo, and occasionally more complex things like grain elevators. What she understands about engines would fill less than a thimble, but this much is clear even to a ten-year-old: To work, engines need fuel.

So she flows with the blue, and the sapphire’s power flows through her. The vine in her hands seems to gasp at the sudden influx, though this is just her imagination, she’s sure. Then it hums in her hands, and she sees how the empty, yawning spaces of its matrices fill and flow with glimmering silver light, and something immediately shunts that light away to somewhere else —

A loud clack echoes through the cavern. This is followed by other, fainter clacks, ramping up to a rhythm, and then a rising, low hum. The cavern brightens suddenly as the blue pylons turn white and blaze brighter, as do the tired yellow lights that they followed down the mosaic tunnel. Nassun flinches even in the depths of the sapphire, and in half a breath Schaffa has grabbed her away from the vine. His hands shake as he holds her close, but he doesn’t say anything, his relief palpable as he lets Nassun flop against him. She’s suddenly so drained that only his grip holds her up.

And in the meantime, something is coming along the track.

It is a ghostly thing, iridescent beetle green, graceful and sleek and nearly silent as it emerges from somewhere behind the glass column. Nothing of it makes sense to Nassun’s eyes. The bulk of it is roughly teardrop-shaped, though its narrower, pointy end is asymmetrical, the tip curving high off the ground in a way that makes her think of a crow’s beak. It’s huge, easily the size of a house, and yet it floats a few inches above the track, unsupported. The substance of it is impossible to guess, though it seems to have… skin? Yes; up close, Nassun can see that the surface of the thing has the same finely wrinkled texture as thick, well-worked leather. Here and there on that skin she glimpses odd, irregular lumps, each perhaps the size of a fist; they seem to have no visible purpose.

It blurs and flickers, though, the thing. From solidity to translucence and back, just like an obelisk.

“Very good,” says Steel, who is suddenly in front of them and to one side of the thing.

Nassun is too drained to flinch, though she’s recovering. Schaffa’s hands tighten on her shoulders in reflex, then relax. Steel ignores them both. One of the stone eater’s hands is upraised toward the strange floating thing, like a proud artist displaying his latest creation. He says, “You gave the system rather more power than absolutely necessary. The overflow has gone into lighting, as you can see, and other systems such as environmental controls. Pointless, but I suppose it does no harm. They’ll run down again in a few months, without any source to provide additional power.”

Schaffa’s voice is very soft and cold. “This could have killed her.”

Steel is still smiling. Nassun finally begins to suspect that this is Steel’s attempt to mock a Guardian’s frequent smiles. “Yes, if she hadn’t used the obelisk.” There is nothing of apology in his tone. “Death is what usually happens when someone charges the system. Orogenes capable of channeling magic can survive it, however – as can Guardians, who usually can draw upon an outside source.”

Magic?Nassun thinks in fleeting confusion.

But Schaffa stiffens. Nassun is confused by his fury at first, and then she realizes: Ordinary Guardians, the uncontaminated kind, draw silver from the earth and put it into the vines. Guardians like Umber and Nida can probably do the same, though they would try only if it served Father Earth’s interests. But Schaffa, despite his corestone, cannot rely on the Earth’s silver, and cannot draw more of it at will. If Nassun was in danger from the vine, that was because of Schaffa’s inadequacy.

Or so Steel means to suggest. Nassun stares at him incredulously, then turns back to Schaffa. She’s getting some of her strength back already. “I knew I could do it,” she says. Schaffa is still glaring at Steel. Nassun balls up her fists in his shirt and tugs to make him look at her. He blinks and does so, in surprise. “I knew! And I wouldn’t have let you do the vines, Schaffa. It’s because of me that —”

She falters then, her throat closing with impending tears. Some of this is just nerves and exhaustion. Much of it, though, is the sense of guilt that has been lurking and growing within her for months, only now spilling out because she’s too tired to keep it in. It’s her fault that Schaffa has lost everything: Found Moon, the children he cared for, the companionship of his fellow Guardians, the reliable power that should have come from his corestone, even peaceful sleep at night. She’s why he’s down here in the dust of a dead city, and why they’re about to entrust themselves to machinery older than Sanze and maybe the whole Stillness, to go to an impossible place and do an impossible thing.

Schaffa sees all this instantly, with the skill of a longtime caretaker of children. The frown clears from his face, and he shakes his head and crouches to face her. “No,” he says. “Nothing is your fault, my Nassun. No matter what it has cost me, and no matter what it may cost yet, always remember that I – that I —”

His expression falters. For a fleeting instant, that horrible, blurry confusion is there, threatening to wipe away even this moment in which he means to declare his strength to her. Nassun catches her breath and focuses on him in the silver and bares her teeth as she sees that the corestone in him is alive again, working viciously along his nerves and spidering over his brain, even now trying to force him to heel.

No, she thinks in a sudden fury. She grips his shoulders and shakes him. It takes her whole body to do this because he’s such a big man, but it makes him blink and focus through the blur. “You’re Schaffa,” she says. “You are! And… and you chose.” Because that’s important. That’s the thing the world doesn’t want people like them to do. “You’re not my Guardian anymore, you’re —” She dares to say it aloud at last. “You’re my new father. Okay? And th-that means we’re family, and… and we have to work together. That’s what family does, right? You let me protect you sometimes.”

Schaffa stares at her, then he sighs and leans forward to kiss her forehead. He stays there after the kiss, nose pressed into her hair; Nassun makes a mighty effort and does not burst into tears. When he speaks at last, the horrible blurriness has faded, as have even some of the pain-lines around his eyes. “Very well, Nassun. Sometimes, you may protect me.”

That settled, she sniffs, wipes her nose on a sleeve, and then turns to face Steel. He hasn’t changed position, so she pulls away from Schaffa and goes over to him, stopping right in front of him. His eyes shift to follow her, lazily slow. “Don’t do that again.”

She half expects him to say, in his too-knowing voice, Do what? Instead he says, “It’s a mistake to bring him with us.”

Cold washes through Nassun, followed by hot. Is it a threat, or a warning? She doesn’t like it, either way. Her jaw feels so tight that she almost bites her tongue trying to speak. “I don’t care.”

Silence in reply. Is this capitulation? Agreement? Refusal to argue? Nassun doesn’t know. She wants to yell at him: Say you won’t hurt Schaffa again! Even though it feels wrong to yell at any adult. Yet she has also spent the past year and a half learning that adults are people, and sometimes they are wrong, and sometimes somebody should yell at them.

But Nassun is tired, so instead she retreats to Schaffa, taking his hand tightly and glaring back at Steel, daring him to say anything else. He doesn’t, though. Good.

The huge green thing sort of ripples then, and they all turn to face it. Something is – Nassun shudders, both revolted and fascinated. Something is growing from the weird nodules all over the thing’s surface. Each is several feet long, narrow, featherlike, attenuating near the tips. In a moment there are dozens of them, curling and waving gently in an unfelt breeze. Cilia, Nassun thinks suddenly, remembering a picture in an old biomestry creche book. Of course. Why wouldn’t people who made buildings out of plants also make carriages that look like germs?

Some of the feathers are flickering faster than others, clustering together for a moment at a point along the thing’s side. Then the feathers all peel back, flattening against the mother-of-pearl surface, to reveal a soft rectangle of a door. Beyond, Nassun can see gentle light and surprisingly comfortable-looking chairs, in rows. They will ride in style to the other side of the world.

Nassun looks up at Schaffa. He nods back at her with jaw tight. She does not look at Steel, who hasn’t moved and makes no attempt to join them.

Then they climb aboard, and the feathers weave the door shut behind them. As they sit down, the great vehicle utters a low, resonant tone, and begins to move.

***