The first time I entered the asteroid habitat’s nave, that vast interior space was still cold and dark. The hab’s bones remained trapped under ice—and that ice was why I’d been called away from my own tasks. Someone on the Nave Architecture team had found out I could help them determine which way the water would eventually flow when, months from now, the cylinder of Ecbatan finally warmed through completely and power could be redirected to the axial longsun, filling the nave with light. We called that glowup.

I needed to find a nave architect named Efrem but had yet to see anyone in that roaring dimness, as air currents circulated and equalized temperatures. Somewhere on the curved surface on the opposite side of the nave’s cylinder, three kilometers from where I stood, a small constellation of glowing pinpoints showed where repair work was going on. A sudden gust of wind blew ice chips at me, but my environmental suit kept me warm, if not happy.

I was annoyed with myself for leaving “accurately predicting the behavior of ice and water under changing temperatures in rotating habitats” in my list of skills. Desperate to get on the team tasked with bringing Ecbatan back to life, I threw everything I had at the job rec for a placemaker on this big hab rehab. I’d gotten the job and so had to live with the consequences.

My area of responsibility was reconfiguring the tangle of passages and vacuoles in the hab’s rind, its thick outer layer of rock. Staffing problems had left me overworked and alone. I did interact with other crews, like Airflow, Systems, and Power/Reactor, but mostly for deconfliction—that is, how we could best avoid each other. Meetings were quick, just an exchange of jargon and diagrams. The initial project team, around 180 people, had been here a month, but I’d been too busy to really meet anyone else.

My feeling of isolation had been the real reason I’d accepted this task: I’d seen that Efrem was a center of several social networks, particularly one group of interesting-seeming people from several different crews and habs of origin. But he was nowhere to be seen. While looking for him, I passed someone I’d met on the shuttle over, Tremont from Airflow, but the roar of the vortex cannon he was using to move debris was too loud for him to hear me. At that point, Tremont was nothing but a tenuous social contact. I had no idea how deeply involved in my life he already was.

I put on my crampons and walked my assigned zone, a rocky area that, when the nave’s water finally melted, would be a rocky peninsula sticking out into cylinder-girdling Cincture Lake. An inlet at the peninsula’s end led to a sheltered spot, a perfect place for a beach, with a picturesque stone structure above it. I’d defined it right, because, more than a decade later, I took my children to play on that beach. They didn’t believe me when I told them it had all once been dark and covered in ice. It’s always hot and sunny there now.

The ridgeline that formed the peninsula climbed away from the lake to where the cylindrical space of the nave ended in the vertical rock of what we in the rehab team called the Home hub, since that was where we had landed and made our base. Ecbatan’s Away hub, far off on the other side of the future lake, was invisible in the darkness.

From a high spot above the inlet, I got a good view of the mounds and spires of the frozen lake as well as places in the complex landscape where ice formed in the weeks and months after Ecbatan had been abandoned and left to cool. I marked my observations on my tab: there was a wide area above the inlet, between this ridge and a lower one, where meltwater would pool and possibly even refreeze temporarily.

Above, out of my area of responsibility, I saw where big ice chunks rested in sheltered hollows on the rocky face of the Home hub. That might be interesting when it melted . . .

I spotted the tall figure of Efrem in the lower area along the future lakeshore, his long cloak streaming dramatically behind him. I waved. He looked up at me and yelled something, but the air current tore his words away. I tapped my tab with my observations. I saw him give me a thumbs-up in thanks before his approval popped up. After that, there was no reason to stick around.

Getting down that ice-covered slope was more ticklish than getting up it. I was so intent on where I was putting my feet that I almost stepped on someone laying out translucent green biopackages in a sheltered area near where a stairway led down into the rind.

“Oh!” I said. “Sorry.”

A short figure jumped up. “Hey, Prosper.” A few strands of dark hair stuck out from under her hood. “Think you’ll make it to the party tonight?”

I thought her name was Ishpi, though I wasn’t completely sure. Seems odd to think about that now.

“Definitely,” I said, even though I only vaguely remembered the announcement of the event. “I might see you there.”

Then I descended into my realm, the rocky outer layer of the rotating cylinder of Ecbatan.

---

The entire tangle of corridors and vacuoles in the rind had been planned while the asteroid that became Ecbatan was nothing but a bunch of chondritic rubble, barely held together by gravity. The creation team first mined the water and collected it along the axis, surrounded by a layer of insulating aerogel. They girdled the asteroid with nanofiber mesh, spun it up until it was rotating once per minute, and then exposed it to the searing heat of solar arrays. The rubble melted together and slowly liquefied down to the core. The insulation protected the water from the intense heat until thermal fuses blew at precise instants, leading to an explosion of superheated steam that popped the unnamed asteroid into the complex structure of what became Ecbatan.

I wanted to understand how Ecbatan’s placemakers had then modified those spaces to suit human habitation, how that had ended up working. Only then could I decide what should be rebuilt and what should be transformed. Because of staffing problems and a malfunction in a resupply shuttle, the rest of the Placemaking crew was delayed, and I worked alone. The Safety crew, back in the Home hub, had marked safe areas and kept track of my location. While lighting had been restored in many places, I sometimes had to rely on my head and shoulder lamps. I had an air supply too, though Airflow’s work over the past weeks had pushed breathable air pretty much everywhere.

Over the past few weeks, I’d fallen in love with the elegance of these corridors, parks, and playgrounds. Ecbatan’s placemakers liked sight lines ending in distinctive visual features: obelisks, cupolas, even a gigantic human ear cast from indestructible blue glass. Every destination was a mystery. Corridors kinked, and you would find yourself in a compact space where various traffic flows came together. Changes in texture and other design elements marked when you left one neighborhood for another.

These articulate spaces were laid out at the hab’s beginning. But as time passed, and new generations arose, things had changed. I could see from much later stone walls, fortifications, and hidden escape routes that a civil collapse had engulfed Ecbatan’s society. I marked out where reconstruction would free these spaces again, as well as what larger changes would be required to accommodate the population that would eventually live here.

Some hours later, I found myself on a swooping curved walkway through a large vacuole with ranks of elegant housefronts climbing its sides. But the walkway was blocked by a fortified checkpoint, and the dwellings peered out at the world through the narrow slits that were all that remained of their windows.

Seeing how things had gone badly wrong, I thought about how I might have laid things out differently, eliminating potential flash points, keeping the peace . . . But it never made sense to lay out spaces specifically to prevent the recurrence of some past disaster. That just resulted in a sense of fossilized paranoia that stressed things right from the start.

It was there, where that glorious sweep of walkway ended in a barred checkpoint, that I started to think about staying in Ecbatan after my work contract was up. I’d done three big jobs in my career but never felt the urge to stay on before. Ecbatan felt worth reviving and then becoming part of. Though why I thought my presence could help keep the social structure together was a mystery to me, even now. I’m not even that easy to get along with.

I sensed a change in air pressure and heard a rumble. Airflow was moving large volumes of air somewhere. I remembered what Ishpi had reminded me of: a day-end gathering of everyone not absolutely on duty. She was friends with Efrem, as well as a few other people I thought seemed interesting.

I’d been delayed by my meltwater inventory in the nave and then sunk deep into my planning in the rind. I was startled to see how late it was: the party must already have started. I came close to deciding not to even try to get there, then realized there was a longitudinal transit corridor just below me. This far out in the rind, it was nearly one gravity. That meant I could run at a good speed without bouncing too much. The Home hub was only a kilometer or so away. There were a few piles of debris on the way, but Safety had marked them all as passable.

And those partial blockages were barely noticeable until I came to where someone late in Ecbatan’s decline had blocked the corridor with salvaged wall panels. A doorway led to a passage that went sharply to the left, then just as sharply back right again, forming a V: a defensive baffle, designed to slow and separate any group of attackers so that each could be dealt with individually.

Beyond it was a section of corridor that had served as a strongpoint, seemingly built around the water pump that served this part of the rind.

The baffle had barely slowed me down, but the corresponding one on the other side was a different story. This angle was jammed with debris, fragments of everything from dishes to wheeled toys, covered with a felt of dust, hair, and cloth fragments. It was freshly blown in, still grunting and ticking as it settled. I realized I’d heard the rumble of its being blown in. I dug at the soft mass with my fingers, but that just got me a stream of grit on my shoes. It would take hours to get through. Airflow was getting too casual with where they dumped their detritus.

There were other routes, but they would all require long detours, ensuring I’d miss the party’s end. If I could get through this way quickly, I still had a chance to make it.

I stepped back and examined it. Maybe the baffle itself, made partly of large stone chunks, would be easier to dismantle. That big square block partway up looked like the base of something . . . After a couple of minutes, I managed to get my fingers around the edge and wiggle it back and forth until it came loose.

It proved to be the carved stone bust of a stern-looking woman, short-haired and high-cheekboned, who refused to be cowed by the disasters that had overcome her hab since her death. I set her down out of the way and noted her on my tab for someone from the Cultural Archives crew to check out.

The bust had held the baffle’s structure together, and with it gone, I could pull a panel aside to let the debris cascade out over my feet. Then I climbed through and into the corridor beyond.

---

If I hadn’t been in such a hurry after making it through that second baffle, I might have paused to think about why I had been running into similar obstacles since getting to Ecbatan and figured things out sooner. Instead, I sprinted the rest of the way to my quarters, ripped my insulating suit off, getting crap all over everything, and left without even changing my shirt.

By the time I made it to the party, the light under the dome of the tall circular space was growing brighter to mark the event’s end. Colored paper airplanes looped lazily around the room’s perimeter, getting lower and lower. Someone from Airflow must have lofted them up under the dome at the party’s start.

The last people wandered up the stairs that spiraled up around the circular space and vanished through arched doorways or paused at the various junction points to look down or across the deep space and see who else was coming and going. I didn’t see Ishpi, but I did spot a couple of friends of hers: Amelon, a slender gold-skinned man who was smiling at someone down on the floor, and a big woman with dark amber skin and blond spiked hair, who towered over him. I didn’t know her name.

I hadn’t ever talked to either of them but found myself waving. Amelon raised a hand in response, though it was clear he wasn’t sure who I was. The tall woman lowered pale eyebrows disapprovingly, but maybe she wasn’t looking at me.

Then they vanished through the doorway.

Yeah, I get it: I often felt out of place, so I decided to make my placemaking my career. But then, socially skilled people are rarely conscious of how their sociability works. I comforted myself with the thought that it takes an outcast to truly understand the inner functioning of a community. Someone who’s really had to do the work.

Just as I decided to overcome my natural resistance and follow them up the stairs, something smacked me on the back of my head.

I grabbed at it and came up with the crumpled remains of a broken paper airplane. As I was staring at it, befuddled, a lush perfume filled my nostrils. A woman named Mira brushed past me. She was friends with the two I’d seen on the stairs, Amelon and the tall woman.

Mira tugged at her long black hair and glanced back at me. “So, are you coming or not?”

Before I could formulate a coherent reply, a male voice behind me said, “We’ve still got a lot of work to do on the topography. You go ahead.”

I turned to see Efrem, the nave architect I should have talked to that morning. His cloak looked almost as dramatic draped around his wide-shouldered frame here as it had snapping in the winds of the dark nave.

Mira brought her eyebrows together, a look I certainly wouldn’t have wanted to get, but Efrem was immune to her disappointment. He grinned at me. “Thanks for the help with the ice. The melt’s going to be tricky.” Then, before either Mira or I could say anything, he strode off through a doorway.

Mira now seemed at loose ends. “But where did everyone go?”

She was talking to herself, but I found myself answering: “Amelon and his friend went up the stairs and out the door leading to the upper gallery.”

She seemed a bit startled to see me still there. “Rozalia? Thanks . . . ah . . . ”

“Prosper,” I said. “I’m in Placemaking and Social Design.”

She reached out and pulled something off my collar.

Instead of the piece of paper airplane I was expecting, her slender fingers held a blue-green insect wing case. “An eater of the dead. Beautiful. But where have you been spending your time?”

I took it from her, but before I had a chance to answer, she had gone up the stairs to join her friends.

Such beetles were always part of a hab’s internal ecology, devouring dead flesh and other waste, while never touching anything living. At some time in the past, someone had taken a fairly bland-looking planetary bug and genetically modified it into a work of art, reasoning, I supposed, that a hab needed all the beauty it could get, even if it was crawling over the bones of the dead.

The wing case must have stuck to my suit in that clogged baffle, then to my shirt when I yanked the suit off in a frenzy to get here. While iridescent blue-green, at some angles it flickered red, almost subliminally, as if being hit by a laser—the effect was impossible to reliably repeat.

Thirty years later, I still have it, along with a few other treasures from that time. Every time I pull it out, it seems to represent something different, but interestingly, never death.

Not yet, anyway.

---

A week or so later, I was examining a vacuole, large at the top and narrowing as it descended, that held a cemetery. Illumination came from odd angles, from light pipes fed once again by the solar arrays that thrust out from either hub. A breeze blew steadily up past me as I descended through the cemetery’s various levels.

Monuments in such cemeteries were purely memorial cenotaphs. In a hab, no body was ever wastefully preserved: those beautiful beetles took care of the flesh, and bone gnats feasted on what was left. There had once been a fashion for carving memorial busts with a hint of a corpse beetle behind the ear or just poking out of the hairline. The woman whose bust I’d recovered from the baffle had disdained such fads.

But no artistic detail was left here. Statues had been smashed, dedications chiseled away, metal decorations stripped off. I knew how badly these internal conflicts could go but was still startled by how clearly the feeling of rage still lingered.

My tab’s Safety data showed me that a couple of other people were nearby, and I finally came around a rock projection and saw one of them: a short, stocky man with curly hair named Brak, squatting in front of what looked like it had once been a statue of a child. The position of what was left of its elbows and back indicated it might have had its face in its hands.

He heard my step and looked up, startled. “I thought you were coming from . . . oh, Prosper. I was expecting Rozalia; she’s meeting me here.” He looked up past me, into the wide, dramatically lit space overhead. “This must have been a beautiful space once.”

“I’m hoping it can be again,” I said.

“I’m glad you’re working on it,” he said. “Did you see any intact busts further up?”

“No. The destruction seems to be total. Are you Cultural Archives?”

I thought he knew Amelon, Mira, and a couple of other people in the group, but hadn’t met him before.

“Yeah,” Brak said. “I was hoping to get my hands on the DNA samples they put in their funeral monuments—the last remnant. I’m trying to identify whether any of them settled elsewhere in the solar system after they left and left descendants. But the fight was so bitter that each side tried to annihilate even the biological memory of their opponents.”

We both contemplated how badly things could go wrong when you took things for granted. The breeze had dropped, and the air now felt damp and close. The space was utterly silent.

That bust was still on my mind. “I don’t know if it will help you, but in the last period of the struggle, they reused any rubble they could find for defensive purposes. I found a well-preserved memorial bust as part of a fortification. It probably came from here.”

“That would be great!” Brak said. “I have assigned work today, but could you guide me there at some point?”

To show how good I was at actual human socializing at that point, I almost pointed out that I could just give him the coordinates and he could find it himself whenever he wanted. Just in time, I realized he wanted us to do it together, so we had a chance to get to know each other.

“Of course,” I said, after what must have seemed an oddly long pause.

“Dammit!” The tall woman I’d seen as the party broke up emerged from the narrow lower part of the cemetery. Rozalia’s previously spiky blond hair was disheveled and flecked with what looked like bits of paper. She saw me and stopped.

“Prosper here was just scouting out this cemetery.” Brak tried to fill the silence. “He might be able to help me with my DNA hunt.”

“That’s great.” Rozalia flicked fingers through her hair, dislodging bits of detritus, but not making much progress.

“Are you okay?”

“Oh, you know.” Unexpectedly, she turned to me. “Why is your buddy such a jerk?”

“Who?”

“Tremont. He likes to think he’s funny, blowing everything around the way he does. A couple of weeks ago, he blew a huge amount of crap down the lower transit corridor, almost tore my face off.”

“I don’t know him well,” I said. “Do you think I do? Did he say something about it?”

“Oh, I don’t talk to him. It’s just that he seems like he’s always kind of around while you’re out, with all his gear. I thought maybe Airflow had assigned him to you as your personal ventilator or something.”

That led me to remember the first time I’d seen her. “Early on, in the first couple of weeks, I saw you and Amelon in an upper corridor, going through some salvaged equipment. Was Tremont—”

“Oh, he’d been making mist all over the place, really annoying. Then you showed up. In a hurry, ran right past us.”

“I’d run into some unexpected icing in the corridor. I was really late. Sorry I was so rude.”

“Oh, you weren’t . . . hey, Brak, should Prosper come along with us?

“Where? Oh . . . sure, why not?”

“A couple of people in Biome have started what they’re calling a restaurant,” Rozalia told me. “They’ve absconded with a few tables and chairs and are raising some critters: meat bugs, crayfish, truffle grubs, that kind of thing. And some fungal spices.”

“Maybe the beginnings of an Ecbatan cuisine,” Brak said.

“I wouldn’t oversell it,” Rozalia said.

Biome? Maybe that meant Ishpi was involved. Brak gave me the details. The ventilation started up again as we parted, blowing fresh, cool air, which picked up the paper flecks Rozalia had flicked from her hair and swirled them around.

---

I proceeded down through the rubble of the cemetery’s destroyed monuments to the rest of that day’s survey. I’d been promised the imminent arrival of the rest of my Placemaking crew, but so far, there was no sign of it. I was still on my own.

It was odd that Rozalia thought I was somehow friends with Tremont. Tremont never seemed to think so. We’d both come in on the same shuttle, and “shuttle buddy” was a known kind of relationship, useful to build from when you were just getting started.

As I got back to work, I wondered at how anxious I felt. Was it just the idea of sharing some food with people I wanted to get to know? Or that Rozalia had impulsively invited me along to make up for accusing me of somehow conspiring with Tremont, and Brak hadn’t seemed ready yet to go that far?

No. That would have been just normal social anxiety. I knew how that felt. This was more severe.

I told myself the cause was the confining feel of the city within a city I was examining, hidden behind its makeshift fortifications. It had held as many as fifty thousand people at one time by turning one-time public spaces into cramped habitations. Then all of those people had left a place that had become intolerable and vanished. Maybe Brak could figure out where they had gone. I just wanted to make sure that no one who lived here in the future would end up like that.

I felt a slight change of pressure, and maybe a subliminal thunk through my feet. Suddenly, my heart was pounding. The threat didn’t come from these self-imposed prisons. It came from someone I knew.

I went past communal kitchens, grease still marking the walls, and through a lower corridor that went by a dormitory area—only to come face-to-face with a smooth metal wall. It wasn’t part of the fortifications. This was an emergency seal that reacted to catastrophic breaches in atmospheric containment, and I had felt it slam closed. Had everyone on the other side been exposed to a vacuum through some catastrophic blowout?

My call to Safety probably sounded a bit panicky, but I was greeted with a bland answer: no atmospheric breaches, everything was normal. But that tripped emergency seal was concerning. Did I need help?

I said I didn’t, thanks.

This kind of sliding seal with its locking mechanism had been standard among the asteroid habs for centuries. Mechanical links to two separate sensors, one a diaphragm that detected a pressure differential, the other a spinner that responded to airflow, pushed against a trigger until it released a tightened spring, and slammed the door shut. It had no electronics and required no power, save the muscle power to open it again.

Once there was no pressure difference and no airflow, a pawl would snap back, unlocking the release lever so that someone could pull the door back, retightening the spring and resetting the trigger.

But the lever refused to move, which meant that the door still sensed either a pressure differential or an airflow. But there was no sign of either.

I listened at the seal. At first, I couldn’t hear anything. But was that a periodic thump on the other side, every ten or fifteen seconds or so, very faint? I was pretty sure that something was blowing a jet of air—or, more likely, periodically shooting a vortex ring—against the flow sensor just often enough to keep the release locked down.

Tremont. I didn’t know exactly what he was up to, but I was now sure he was the one who was behind what had been happening to me.

---

Despite my certainty, I felt I had to check what I had previously dismissed as problems normally encountered when restarting a hab, but now it seemed like part of a pattern.

The first was the one Rozalia had mentioned. I climbed up to the corridor where she had seen me . . . and Tremont. I’d been coming back from a survey, anxious to get to a mixer dinner with a couple of other crews, when the corridor filled with dense mist. This happened pretty often, a consequence of pressure and humidity changes. It cleared quickly but had deposited an invisible layer of ice on the floor. The first time I fell seemed like my own fault. So, I stood up . . . and slipped again, hurting myself this time. Even crawling on all fours was difficult and slow, as if I no longer had any grip on reality. In the lower gravity, it had taken an indecent amount of time to get to solid ground.

When I got to the far end and stood up, I felt a brisk, dry air current in my face. When I looked back, that breeze had sublimated every bit of the ice as if it had never been. Despite my hurry, rushing past Amelon and Rozalia, the dinner had been almost over when I got to it.

Now it was just a corridor. I wasn’t even entirely sure which stretch of it had become so icy.

Three weeks after that, I was late to a meeting with some people from Airflow, not including Tremont, to go over plans for a large section of the rind. I knew a shortcut through a hatch that accessed the shuttle supply area. But when I got to it, it stayed stubbornly shut even though it was clearly unlocked. I missed that meeting entirely and suspected I had started to get a reputation for being unsociable and unreliable.

Now the hatch floated open at the barest touch. I poked my head through and looked down the curving wall, past strapped-down shuttle gear. I don’t know what I was expecting to see. I had a feeling airflow had something to do with that mysteriously sealed hatch but couldn’t figure out exactly how.

I felt my resolution weakening. What proof did I actually have? Maybe my problems were just the consequence of being overworked and often late.

I remembered a slightly tense encounter with Tremont, early on, not long after the two of us moved into the dormitory area. That event didn’t seem so big, but that was all I had right now.

That made me doubt myself even more. What was the real evidence that Tremont was deliberately interfering in my attempts to get to know anyone? Who would care about my miserable social life enough to try to make it even worse? I was uneasily aware that paranoiacs wish they were important enough for people to spend time and effort plotting against them.

---

But I didn’t turn around. I entered the Airflow storage facility through an iris closure that dilated and contracted like a human eye. It was typical of the kind of show-offy tech Airborne liked to use.

This was near the hab’s axis, and like most low-gravity storage, the Airflow closet was high and narrow, with clamp-covered storage grids and vertical conveyors to carry equipment up and down. Large pieces of gear hung many meters above in the half-light. I saw Tremont’s hunched back amid dangling power cords with glowing connection points and small racks of spare parts. He was working on the open rear of a barrel-shaped vortex cannon, a meter and a half long and a meter in diameter. I suspected that this was the device he’d set up to spoof the emergency seal.

“Looks like that thing gets a lot of use,” I said.

His shoulders jerked. He didn’t turn around. He kept working on his repair for long enough that I thought he might ignore me completely. Finally, he finished, though, and straightened up.

He was loose-jointed, thin, and taller than I was. He squinted at me. His eyes were narrow under his bulky forehead.

“It’s one of our most useful tools,” he said. “Extremely efficient. Does malfunction frequently, though. Have to keep on maintenance.”

“I think you know how to use everything here.”

“Do you want a tour?” It was as if I’d come in just to get an introduction to Airflow’s valuable work. “I’m busy, but I might have a minute or two—”

“In the past few months, I’ve encountered an unexpectedly icy corridor, a safety door shut by some kind of airflow, baffles crammed with blown-in debris, and a fail-safe emergency seal shut for no reason. Each of them was enabled by one of your pieces of equipment. Operated by you.”

At that point, I had no idea which pieces of gear I could see around and above me that he might have used to block me out, though I would eventually learn.

Even though I remember everything that happened, I’m startled in retrospect at my certainty—and by the fact that I was actually right. It really was just an inspired guess, based on Rozalia’s casual observation about Tremont’s presence around me, which could have simply been based on her dislike of the man.

It was clear that the list of blockages had an effect on him. Creases appeared on his big forehead. He’d done his best to act deniably. Now it was out in the open.

“You work far out ahead.” He shot each phrase out, with a pause after each one. “Dangerous work. We do puff air. Prevent oxygen depletion. Keep the temperature stable. Sometimes it might affect you.”

“It was a lot more than puffs of air,” I said. “I was deliberately blocked out every time. If someone looked at what equipment you checked out when, what would it show?”

“It would show that I’m really busy.” He thought of something. “Did you report any of these incidents?”

“What? No . . . it took me a while to figure out what was going on. At the time, they didn’t seem like ‘incidents.’”

“Nonexperts shouldn’t try to diagnose airflow problems on their own,” Tremont said. “Things do go wrong. Anomalies. Resonances. We can’t figure them out if we don’t know about them.”

“Each time,” I said. “Each time I was on my way to meet someone, get to know them. And each time I was blocked, isolated, walled off. Each time!”

I’d come to confront him, but I was the one losing my cool.

“If you want to give me the times and places you encountered airflow-related difficulties,” Tremont said, “I’d be happy to help you make out the reports. We always want to improve our processes.”

I couldn’t stand it. “I just want to know why! Why are you doing this? There must be something you can say.”

His lips parted—but then shut again. I’d never know how close he came to being honest with me. He flicked a finger at a control and said, “I can say that I have to get back to work now.”

I heard a whisper of sound behind me, and saw that the door had irised halfway shut, leaving an opening I’d have to climb through. The pettiness of that relaxed me, made me see him as less threatening.

“Look,” I said. “If I was sharp with you when you blew over my model—”

“Don’t take your inability to make friends out on me,” Tremont said.

A surge of anger took me by surprise. I took a step toward him—and stopped. What did I think I would do next? Hit him? Even if I took a swing, a fistfight in low gravity was more like a drunken pillow fight, useless and ludicrous.

But he stumbled back behind his vortex cannon and turned it.

A blast of air blew me backward through the remaining aperture and let me fall without.

“I do know how to use this thing,” Tremont said.

The door irised shut.

---

The next day, I almost didn’t go to meet Brak and show him the bust. After my encounter with Tremont, I hadn’t wanted to see anyone, and so had skipped that dinner, and once again disappointed those I most wanted to get closer to. Maybe Tremont was right: I was just looking for a scapegoat for my own social failures. I’d stay in bed, scheming on how to redesign the entire hab so I could trap Tremont in a dead end from which he would never emerge.

Then I realized failing to meet Brak would be something else I would regret. Failing less often was a possible path to a life less filled with regret. It was worth a shot.

Brak was already at the collapsed remains of the baffle when I arrived, kneeling in front of the bust. The debris that had blocked the baffle was gone, blown away by Tremont.

He’d been complete about removing any traces of his actions, as I discovered when I tried to raise the issue with his superiors in Airflow. They had no interest in pursuing my hard-to-substantiate accusations. People always blamed their problems on vagrant air currents. They were tired of it. Though Tremont’s performing maintenance on a piece of equipment without properly powering it down was definitely a safety violation, thanks for reporting the incident.

Brak looked up. “Hey.”

“Hi.” He might have been a bit tentative, but he was here.

“You found this in the baffle?” he said. “Do you remember exactly where?”

I was able to show him the way the bust had served to hold that part of the baffles together. Together, we then located other pieces of broken sculpture that seemed to come from that same cemetery.

He regarded the dead woman’s sculpted face intently. “Her memory must have been important to them, even after things fell apart. They protected her bust. Only near the end, at the edge of survival, did they use her bust for self-defense.”

“Can she help you?” I said.

“I’m pretty sure her DNA is still there. She can provide us with the information we need to identify her descendants.”

When it came time for lunch, it turned out he’d brought me food. He must have gotten some sense of my disordered state. Some was leftovers from the night before, the meal I had missed. The bug pâté was particularly tasty.

“What do you know about Tremont?” I said. “I met him on my shuttle in, but that’s our only bond.”

“Rozalia’s sorry about assuming you were together somehow. But Ishpi . . . you know Ishpi? Biome.”

“We’ve met.” That was so cool, it felt like a lie, even though it was completely accurate.

“They’re both from the same hab. She says Tremont is . . . well, ‘touchy’ isn’t quite the right word. He seems to regard feeling offended as demonstrating a kind of integrity.”

“Can I tell you something that happened with him?” I said.

He hesitated, maybe not ready to be so confidential. “Sure. But you have to decide which fights are worth having. He can really get stuck on things.”

“When I’m trying to understand a problem, I think really hard on it. When I stop making progress, I make a model out of construction scraps and packaging remnants and let my fingers think instead. This was early on, we were all in those curved passages near the shuttle hangars. I’d put together a model to think about a tricky intersection. I looked away to check something, heard a clatter, and turned to find it all in pieces. I looked around the curve, and Tremont was there, working on some airflow thing with a long slot in it.”

“Air knife,” Brak said.

“Is that what it’s called? I don’t even know how he did it, but I knew he was responsible in some way.”

“Coanda effect,” he said. “I know that passage. An air knife can create a laminar flow that clings to a curved surface. You can even remove thin layers from an excavation with one. Can be useful.”

I remembered the hatch outside the shuttle hangar. “Could you use it to make it impossible to open a closed hatch?”

“By moving a layer of air across it, leading to lower pressure? Sure. Not its intended use.”

“Well, knocking over my model was probably an accident,” I said. “He was trying to fix something about that air knife. I didn’t care. I told him, ah, I told him he should learn how to use that thing.”

And he’d finally gotten the chance to throw that phrase back at me. Must have been satisfying.

“Could be that,” Brak said. “Could be something else. Does it matter? He has an ego like a giant soap bubble. How much work are you going to do to maneuver around it?”

I realized that Tremont was just a problem. Some problems could be solved, others couldn’t—and some didn’t deserve the amount of attention it would take to solve them. They could only be controlled.

The real issue lay in what I was going to do about the rest of my life.

“I don’t know what you’re doing for glowup,” I said. “But there’s a lot of ice up in the cliffs above the peninsula opposite. An oddly large amount, actually. I think Ecbatan’s designers set that up to put on a show when it melts. If you guys want to come up when your tasks are done, there might be something to see.”

“What?” Brak was startled. “You think they designed it to entertain whoever finally warmed up their abandoned and frozen hab long after they were gone?”

“More than that, even before initial settlement, they anticipated that the hab they’d designed would someday be abandoned and frozen. So, yeah. They took the long view.” As, I realized, I was. I was definitely planning to stay here and make a life in Ecbatan, even if I had been pretty unsuccessful in creating one so far.

“Efrem’s working.” Brak packed the remains of lunch back into his bag. “He’s Nave Architecture, you know. He might draft some of us on short notice, if anything goes wrong. But I’m sure we’ll see you at some point during the festivities.”

I watched him saunter down the corridor. Maybe we were becoming friends, but he hadn’t clearly responded to my invitation.

---

The longsun had brightened at last, and the vast nave now loomed dizzyingly around me, its surface curving up and around to enclose the space. The ice of Cincture Lake swooped from the base of the cliffs below me to gleam blindingly overhead. The air was full of the sweetish smell of centuries-frozen organics finally getting a chance to rot. I heard the rush of meltwater, and the creaking of the ice, with the occasional sound of a deeper cracking. The increasing amount of water had generated patches of mist and cloud that flowed and periodically screened parts of my view.

Ice requires an incredible amount of energy to melt. The lake, the largest single chunk of ice in Ecbatan, had been warming from below for months, taking most of the output of Ecbatan’s restored 5GW reactor. Now its power could finally be spared to crank up the light-emitting longsun and all the other functions of the hab.

I stood on the spot I’d identified as giving the best view of the Home hub and its eventual cascades during my ice assessment. I was alone. Far off across the ice, I could see balloons, kites, and banners floating up on the central island, lit from below by the glow of radiative roasters. The ground was crowded with almost everyone in the hab. I’d scooped up a pennant to put up where I stood, as a kind of claim.

Now that I’d uncovered his identity, what would Tremont do? He was impossible for me to predict. He could blow me off this cliff. He could melt the ice, isolating me here and forcing me to take a long detour around to get to the party. He could decide that blowing me out of the irised door had made us even.

I told myself this was all beautiful, and if I was going to be the only one with a close view of what I was calling the Coriolis Cascade, then I would have to give it full attention, no matter Tremont’s plans . . . or anyone else’s. Still, I was disappointed.

Below me, I could see that the pool I’d predicted had indeed formed above the stone building and the beach, though it looked significantly larger and deeper than I had anticipated. Why was that?

I couldn’t wait up here if something I’d signed off on was going wrong. I trotted along the ridge and then down.

It was pretty clear what had happened. The ice dam at the pool’s lower end, right above the structure, was significantly larger than I’d anticipated. That stretch of rock must not have heated as much as the rest. Or maybe more debris had blown in to hold it together. But when that dam finally gave way, that amount of pouring water might do serious damage to that stone structure, as well as wash away whatever was left of the beach.

It didn’t matter if Tremont had been messing around, or even if he’d anticipated that my need to correct a problem I could see would take me down into this valley, away from people I wanted to be friends with, and from the best view of the display of cascades. Maybe it was strictly Nave Architecture’s business, but I couldn’t just leave this thing to spill over. I felt responsible for it.

That lower ridge on the other side looked promising. Taking a risk, I skipped across the fragile ice dam over to there.

That ridge was indeed barely above water level, and some of it was just rubble. If water found a gap there, it would pour out in that direction, pouring into the inlet by another route, rather than right over the rock structure.

Any breach would grow quickly, going from a trickle to a torrent in seconds. I had to be careful. Mist had closed in around me.

If I pulled out that rock . . . no. The misty air was warm, the ground underneath was warm, everything was melting, the sound of dripping was everywhere. It was more than I could handle on my own, but if I hesitated much longer, the ice dam above the inlet would finally melt, taking the decision out of my hands.

“Here he is,” someone yelled nearby.

I looked up. Efrem stood just above me, legs spread, cloak thrown over his shoulder, dramatic in the mist.

“Hey,” he said. “We were looking for you up at the view spot you found. But I can see we have a problem here.”

Brak and Ishpi emerged out of the mist as they descended the slope.

“We have to get to work,” Efrem said. “Prosper will direct you.”

Then the rest of them came into view.

---

With half a dozen pairs of hands, clearing a gap without getting caught in it was ticklish, but doable. I could see the differing approaches. Mira was competitive and scouted carefully to pick just the rock most likely to release the water. Amelon focused on where the underlying support was weakest, rather than focusing on the top. Brak got distracted by a couple of stones that had tumbled down from some other structure. Rozalia just put her back into it and moved mass without looking up. Ishpi jumped from spot to spot, never focusing enough of her attention on a single spot to really dig down. Efrem worked as hard as anyone else but also directed others with almost invisible gestures of his fingers and shoulders. Following him, Ishpi tugged a stone above the spot Amelon had identified . . . and several other stones gave way.

I managed to pull her out of the way and set her feet on solid ground. We all skittered back as the flow quickly tore a ten-meter-wide gap in the loose rock. It took less than a minute to drain the entire pool. Rozalia and Brak had gotten stuck on the far side, but, balancing each other, were able to make their way back over the wet rocks. It’s hard to remember them all as I saw them then. Decades of knowing them since has given me an understanding that I automatically add to my memory of their actions.

A breeze had sprung up, clearing the mist. Without water behind it, the ice dam could disappear slowly. The structure below it was now safe. We crossed it and climbed back up the high ridge for the view.

The longsun glowed at full brightness, shining on the dozens of cascades and waterfalls that now came down the cliffs of the Home hub. They spread out in all directions, coming down where we were, but seeming to fly upward when you looked up to the nave’s opposite side. None of the flows went straight. Coriolis force bent each stream of water antispinward, the curve increasing the farther out it went, like a giant pinwheel. Ecbatan’s designers had created pools and spouts that took advantage of that curve at every level.

Was this really the only time anyone would see this sight? All I can say is, I haven’t seen it since, and it’s been thirty years.

The water spilling from the pool had melted what ice had been left in the inlet.

“I’m sorry,” I said. “We can’t get directly back to the party. It’s a long trip to the hub and then back through the rind to the island.”

“Oh, that’s boring,” Efrem said. “We’ll spend our lives doing that kind of thing. This is a special occasion.”

“Brak,” Rozalia said. “Didn’t you say there’s a rescue station down in that thing?” She pointed at the building we had saved from the flood. Any ice on it had melted, and its large blocks of yellowish stone gave it a solid, dry look.

“Oh, yeah,” Brak said. “Amelon and I looked over it. It is a rescue station, and they stored all the gear incredibly well, as if they were hoping to come back. Everything’s really old, but functional.”

“Then we should take advantage of their functionality,” Ishpi said.

“If we don’t,” Rosalia said, “someone will show up to tell us we can’t.”

We hauled rafts and life vests out of the building. Two large rafts inflated neatly, ropes were still usable, paddles were ready. We piled into the rafts: Efrem, Brak, Rozalia, and me in one; Mira, Ishpi, and Amelon in the other. I pushed us off, while Ishpi, with a glance over at me, launched theirs.

It turned into a bit of a race, which might have been unfair, given that we had one more paddler, but Brak, somewhat to my surprise, proved to be truly terrible at paddling, splashing more water over himself and everyone else than he managed to pull behind the raft. That evened things up.

“Any luck with the DNA in that bust?” I asked Brak, hoping to keep his paddle out of the water.

“It’s an interesting story.” Brak swung around and almost brained me with his paddle. “There was enough genetic information from that bust and a few other places to identify descendants of those who abandoned Ecbatan. The two groups were indistinguishable on the population level. But we’ve identified two settlements that seem to be almost entirely descended from the refugees from this hab. Right now, we’re assuming that one was settled by one group, the other by the other. Neither is in the Belt.”

“Where, then?” I said.

“You’d have thought they’d go in completely opposite directions, but both are on Mars. In the same region of Mars, Daedalia Planum, smack in the middle and almost in sight of each other. The two settlements have low-level controversies over water, over other resources, over who failed to do their share in maintaining the road to Arsia. Sometimes, some illicit boundary-crossing sexual relationship leads to violence, but no large conflicts. The nearest other settlement is at least eight hours away.”

“They have to hang out with each other because no one else will hang out with them,” Rozalia said.

“Hey!” Ishpi yelled from the other boat. “Are you guys going to joke around over there, or are you going to paddle?”

“We concede,” Efrem shouted back.

“You can’t concede,” Mira said. “We’re all in this until the end.”

A breeze came up, and the rest of the mist blew away. We weren’t far from the island. Things seemed to have gotten dull out there because everyone crowded on the shore to await our arrival. So we did our best to make it a race in the last few meters, and actually beat the other boat, mostly because Brak fell back between the thwarts and couldn’t get himself out to splash any more water before we hit shore.

It’s been thirty years, five and a half of Ecbatan’s orbits around the Sun. Things haven’t always been smooth. We haven’t always gotten along. There has been at least one infidelity (not ours), one decade-long estrangement, and a serious, life-changing injury. I have other friends throughout Ecbatan, but these people, the ones I landed on that island with, are still who I rely on most.

As for Tremont . . . He also decided to stay on Ecbatan, though, since that day, I have seen no sign of his interfering with my activities in any way.

I designed a plaza to replace the fortification with the baffles in the lower transit corridor. I left the bust of the unknown short-haired woman as a focal point. Lately, my layout has been constricting movement in that growing neighborhood, and people want to change it. I think it makes sense, but it’s better that someone else does that work. I’ve trained several people who would do well at it.

Tremont is prominent in opposing any changes. He talks about “the genius of the founders.” He doesn’t mean me. He means the original settlers of Ecbatan, whose descendants settled down to a cozy conflict on Mars. I’m not sure he even remembers that the plaza is of my design and replaced a trap he’d set for me. When I get irritated by how comfortable forgetting your past can be, I just go and make a model.

The crowd helped us beach the boats. I had trouble getting out over the lifeboat’s inflated side. Ishpi caught me and kept me from sliding back into the water.

We climbed up the shore and made our way to the party.