The door closed behind them.
Stone met stone with the sound of a decision.
The air changed immediately — old, dry, the specific cold of a space that had not exchanged breath with the surface in a very long time. Their candles held close, the light not so much blocked by the dark as unacknowledged by it. Beyond the first few steps, the darkness didn't absorb the flame. It simply continued without caring whether the flame was there.
Tomo exhaled. "Okay," he said, quietly, as if the word was a test. "This is not a basement."
Xeno had taken two steps through the threshold and stopped. Feet planted. Shoulders set. Not looking around — looking up, with the specific quality of someone who has just estimated a height and found the estimate inadequate.
"What is it?" Aaron said.
"Bigger than it should be," Xeno said.
Shion lifted her candle higher, the instinct of someone trying to push light into a space it hadn't claimed. "Engineered," she said, voice lowered not from fear but from the economy of the space, as if sound had value here and shouldn't be spent carelessly. "They excavated this and reinforced it afterward. The ceiling isn't a cave ceiling. It was made."
Aaron put his boot down carefully, testing the floor before committing weight. The stone was smoother than the service tunnels beneath the palace — not polished in the decorative sense, finished in the functional sense. Made for traffic.
They moved into the hall.
It revealed itself by degrees.
Pillars emerged from the floor at regular intervals, thick as tower bases, each one carved with vertical grooves that ran from base to the invisible ceiling — ribs, almost, the structural notation of something that understood load. The candlelight reached the nearest one and stopped there, but the shadows it cast implied others behind it. A forest of stone. A grid. A system with internal logic.
Tomo slowed. The usual energy that moved through him went still. He tilted his candle toward the nearest column and looked at it for a long moment. "How many people does it take to build something like this?"
"More than a duke commands," Shion said.
"More than an empire," Aaron said.
The words came out flat. Not awe — calculation. The voice of someone noting a data point that required adjustment to an existing model.
Tomo tried a small laugh. The kind he produced when his body needed to manage something and his mouth reached for its most reliable tool. The sound bounced back from the stone walls, altered in transit, arriving wrong. He didn't try again.
They walked.
The air stayed dry. No dust. No damp. No rot. The smell of the space was not the smell of abandonment — abandonment had a specific scent, the specific compound of water and time and the absence of maintenance. This had none of that. It smelled like a room that had been closed carefully, not a room that had been forgotten.
Xeno ran his knuckles along a pillar as they passed. The stone didn't crumble or chalk. It was cold, and it was alive with craft in the way that things were alive with craft when the people who made them had understood their materials.
"This isn't ruin," Shion said, mostly to herself. "It's preservation."
Tomo looked at her. "How can you tell?"
She stopped. Let her impatience surface briefly. "Look at the base." She held her candle close to where the pillar met the floor. Fine lines ran through the stone — too regular for cracks, too deliberate for chance. Interlocking seams. Joints that weren't joints. The notation of modular construction, of something built to be maintained or dismantled rather than simply standing until it fell.
"They built this like a machine," Shion said. "And machines are maintained or sealed. This one was sealed."
Aaron crouched and found the same line running across the floor — thin, unbroken, continuing in both directions past the range of his candlelight. He pressed two fingers to it. The seam was so tight he couldn't find the edge with his nail.
"They didn't lose this place," Aaron said. "They left it."
Xeno's jaw tightened. "Why?"
None of them had anything that wasn't speculation. The silence that followed had more weight than any answer they could have produced.
They came to the first wall.
It was not plain. The carvings began at the base and ran to a height that their candles couldn't reach, layered in depth — nearest figures almost free-standing, distant structures receding into carved horizon. Shion's light crawled over the images: mountains with their faces cut away into stair-stepped cities. Bridges spanning valleys in arcs that understood tension. Halls inside stone, their ceilings held by pillars that made the ones around the group feel like demonstrations rather than structures.
Tomo leaned forward, squinting. "Is that a city inside a mountain?"
"Yes," Shion said. "And not just inside — it's a carved mountain. Deliberate removal. They hollowed it from the top down."
Aaron moved his candle along the relief.
The next scene stopped Tomo's breath.
Above the mountain cities, there were structures in the sky.
Not clouds. Not stylized birds. Geometric masses, floating, tethered by nothing visible. Citadels. Platforms. Towers. Cities suspended in air with the specific detailing of things drawn by someone who had seen them, not imagined them.
Tomo's mouth opened. Closed. "That's — that's symbolic. That's the gods' homes. Every culture has imagery like that."
Shion was tracing the edge of one floating structure without touching it. She didn't answer him immediately.
"Shion," Tomo said.
"Look at the support notation," she said. "The angles. The implied weight distribution." Her finger stopped at a point where a carved line ran beneath one of the floating structures at a specific angle. "They didn't draw this as divine. They drew it as a problem that required a solution."
She turned to look at him, and her expression was the one she used when she needed the person she was talking to to stop finding the comfortable interpretation. "Tomo. They carved gravity into this wall."
Tomo swallowed.
"Sky cities," Xeno said. Low. The voice of someone giving a thought a voice it didn't want.
Tomo looked between them. "We don't have sky cities."
"No," Aaron said. "We don't."
His mind was doing something he didn't say aloud. He was looking at the floating citadel and seeing something he had seen in a previous life — habitat modules, orbital rings, infrastructure so large it became environment. He was looking at the carved bridges and thinking about load distribution and transit arteries. He was looking at the way the ancient carvers had represented tension in stone and thinking: they understood physics.
He didn't say any of that. Not because he didn't trust the people beside him. Because it hadn't finished forming yet, and he didn't give words to things without shapes.
Shion moved down the wall and found text.
Not gallery lAarons. Not decorative. Deep grooves, each character sharp and angular, made with the intention of outlasting whoever carved it. She stopped, and her candle tilted toward it, and she read.
When she spoke, she spoke in Dwarven first — the original language, low and guttural and rhythmically regular, each syllable landing with the weight of something that had been designed for stone acoustics. "Keth varun… sol'drath imir…" She stopped. Moved her finger along the groove. "Kazim dreth, varun sol."
Tomo watched her lips. "What does that mean?"
She exhaled. Translated slowly. "'Cities above the firmament.'" She paused on the last word. "Firmament. That's not contemporary usage. It's an old concept — the layer between earth and sky, the idea that the sky has a surface."
Tomo tried to smile. It didn't hold. "So it really says sky cities."
Shion moved along, candle steady, lips forming the sounds before she offered the English. "Dren'tal kazor — sol ithrek." She narrowed her eyes. "Sol ithrek." She said it again, testing. "Stone that rejected gravity." A pause. "Not 'stone that flew.' Stone that rejected. There's intention in the original word."
Xeno's hand moved to his sword's hilt. Not drawing. Grounding.
Shion found the next line. She read it in Dwarven first, slower this time, working out the syntax. "Keth'dru imir… vel'sol drath… anam keth." Her brow furrowed. Then: "The Age Before Anchors."
Tomo blinked. "Before anchors?"
"Not the object," Shion said. "A concept. The Dwarven word is vel'sol — it means a fixed point, something that holds other things in relation to it. The phrase is describing an era defined by the absence of fixed points." She looked at the wall. "An era before anything was bound to anything else."
Tomo stared at the carved sky cities. "Before they had to come down."
Shion looked at him.
He hadn't intended it to be analytical. But the accuracy of it sat in the air between them.
She moved to the next text. "Sol'reth varun — drath keth imir." Her translation came quieter. "Sky Roads."
The phrase didn't need elaboration.
Tomo looked at her. "Okay. I'm still going to put forward that this might be — look, old peoples liked their stories. This could be religious."
Shion turned to him with the full weight of her patience deployed against her patience running out. "Tomo. They carved stress lines into the bridges. They carved structural joinery into the pillars. They used engineering notation in carvings about flying cities." She held his gaze. "This is not a creation myth. This is an archive."
Xeno said, without looking away from the wall: "Religious metaphors do not need load calculations."
Tomo closed his mouth. Nodded once. The nod of a man accepting a truth he would have preferred to be false.
They kept walking.
The carvings changed as they moved deeper. The mountain cities grew more elaborate. The sky structures multiplied. And then — abruptly — scenes of absence. Empty sky where citadels had been. Broken lines. A carving half-completed, the artist's work stopping mid-figure, as if the event being depicted had interrupted the recording of it.
Shion slowed.
"What?" Aaron asked.
"The tone shifts here," she said. She moved her candle across the new text. "The script is older. Proto-Dwarven. Some of these forms haven't been used in—" She stopped. Leaned closer. "There's something else mixed in with it."
"Mixed in?" Tomo said.
"The strokes here are curved. Dwarven script is angular, angular throughout its history. These curved characters are—" She went quiet for a moment. "High Elven. Old High Elven. A root form."
Xeno turned his head fully for the first time since they'd entered. "Here."
"Not modern High Elven," Shion said. "Something older. Like a predecessor. The relationship between this script and contemporary High Elven is the same as the relationship between proto-Dwarven and what I study." She looked at the wall where the two scripts ran side by side, angular and curved, two languages recorded on the same stone. "They were here together."
Aaron felt something shift — not in his body, in the architecture of what he had assumed he was moving inside. Dwarves and elves, together, carving the same surface. Not separately. Together.
He didn't speak.
Shion worked at the mixed text slowly, and her frustration was visible in the quality of her breathing. "Keth'vel… anam dreth…" She stopped. Tried again. "Keth vel'dru — anam keth imir." She shook her head. "The syntax is wrong. The Elven elements are restructuring the Dwarven grammar. It's like reading a language through the grammar of a different language entirely."
Tomo looked over her shoulder. "What does it say?"
She breathed out and forced a partial translation. "It's referencing an era. The phrase they use for it is — before the empire, before Caelum, before the kingdoms as they exist now." She moved her candle to a symbol carved at the section's head: a crown shape that was neither human nor Dwarven, simpler and more abstract than either, the concept of rulership rather than a specific form of it.
"Keth'dru vel'imir," she read. Then, in English: "First Age. Or the nearest equivalent."
Tomo's voice came out careful. "First Age like the beginning of things."
"First Age like not our beginning," Shion said. "First Age like a beginning that preceded ours entirely."
Xeno spoke low. "Our traditions speak of a first age. But they speak of gods and great beasts."
"Not cities," Tomo said. The word came out small.
"Not cities," Shion confirmed.
Aaron's mind connected the shape without speaking it. A world that had built beyond ground level. A world that had reached the sky. A world that had fallen so completely and so long ago that the people standing under its foundation called it mythology and meant it as metaphor.
He thought about Earth. About how fast information became legend when systems stopped maintaining it. About how completely a civilization could vanish from living memory given sufficient time and sufficient catastrophe.
He said nothing.
They moved on until they found the panels.
Not murals — text slabs. Stone tablets set into the wall, their faces covered with dense script. Some intact. Others cracked in ways that were not the result of time — deliberate impact, tools applied with the specific intention of removing sections rather than destroying the whole.
Shion stopped in front of one of the damaged slabs. "Someone redacted this," she said.
Tomo leaned in. "Why would you do that to something down here?"
"Because information outlives the people trying to control it," Aaron said.
Shion glanced at him. The look was brief but specific — the look of someone who has heard something said in a tone that doesn't match its surface meaning and has filed it for later.
"That was precise," she said.
"It's a pattern," Aaron said. He looked at the damaged sections. "What's intact?"
Shion took out her notebook and charcoal and then stopped, hand paused in the air, looking at the length of the wall. "I can't copy all of it. Even if we had the time."
Xeno said, without turning: "We don't."
"Enough time to get the keys," Aaron said.
Shion began. She moved along the panels with the charcoal moving in short, controlled strokes, capturing repeated structures, noting symbols that appeared at the head of multiple sections, recording anything that looked like it might organize the rest of it.
As she worked, she read aloud — Dwarven first, then English, the habit establishing itself almost unconsciously as a way of processing through both modes simultaneously.
"Sol'drath vel'imir." She moved the charcoal. "Sky Throne. Or — 'Throne of Sky.' The Dwarven construction implies it belongs to the sky rather than being located there." She paused. "And here — "vel'sol drath keth" — Throne of the First Locus." She looked at the marker. "Locus. Not seat. A fixed point. The central anchor of something."
Tomo said, quietly: "A throne under our palace."
"Or near it," Shion said. "Or connected to it."
Xeno: "This is not for children."
Tomo looked at him. "We're not children."
Xeno looked back. His expression didn't carry anger or condescension. It carried the specific quality of someone making an accurate assessment and knowing the accuracy would land harder than anything dramatic would. "We are not ready."
The words settled.
Tomo had no response to them, because Xeno wasn't insulting. Xeno was stating something that he believed was simply true, and the honesty of it removed all the available deflections.
Aaron watched Shion's charcoal pause at a final section of intact text near the lower edge of the last undamaged panel. She read it in Dwarven first, the words slower, as if she needed the original to carry the full weight before she reduced it to translation.
"Sol'drath keth vel'imir — anam vel'dru imir."
Her voice had gone quiet.
She translated it without looking up.
"'Skyborne kingdoms returned to the Sea.'"
Tomo said: "Returned to the sea?"
"The Sea," Shion said, and her voice had changed quality entirely. "That word — vel'dru — in contemporary Dwarven it means ocean. But in proto-Dwarven the compound means something different. Vel is locus, anchor. Dru is origin, source." She closed her notebook. "The Sea Beneath the World."
The phrase moved through the group without anyone repeating it.
The Sea Beneath the World. The thing Aaron's tutors had described as spiritual poetry. The metaphysical background of Aether theology. The formless thing that preceded all formed things, that underlay matter the way depth underlay surface.
Here it was, in stone older than any dynasty, recorded as a destination.
Skyborne kingdoms returned to the Sea.
Not destroyed. Returned.
Shion drew back from the wall and looked at the carvings of the sky cities — the citadels, the platforms, the towers depicted with structural precision by someone who had understood what they were drawing. Her eyes were wide in the way they almost never were.
"This wasn't mythology," she said. Her voice shook once and then steadied. "Was it?"
The candlelight held against the dark.
Tomo's mouth was open. He closed it.
Xeno was still.
Aaron looked at the carved sky cities and at the damaged text slabs and at the joint-lines in the floor running unbroken in both directions and said the only thing he could say that was true.
"We keep moving."
Tomo looked at him. "Toward what?"
Aaron's candle moved forward, toward the place where the reliefs narrowed and the architecture changed — pillars closer together, walls smoother, the air carrying a quality of increasing intention.
"Toward whatever they didn't want found," he said.
Shion closed her notebook. Nodded once. Forced herself back into motion.
Xeno stepped to the front.
Tomo fell in behind Aaron, quieter than he had ever been.
The hall compressed into a corridor — not cramped, ceremonial. The pillars gave way to carved arches. The carvings changed register from documentation to something closer to instruction. Or warning.
And in the stone, faint threads of gold began to appear. Thin at first, then thicker, running through the rock like the mountain itself had been laced with it.
Tomo whispered: "This place is insane."
Shion answered without turning. "It's older than sanity."
Aaron said nothing.
He walked forward. Candle steady. Eyes taking inventory. Behind him, the sound of their boots echoed and returned a breath late.
Ahead, the corridor curved.
The gold deepened.
And history waited, patient and sealed and far larger than the empire that had built itself on top of it and called the foundation eternal.