The descent felt different after Civic Dusk, as if the stair had decided to be courteous. Lantern light laid itself along handrails instead of fighting them, and damp stone smelled less like last night's fear and more like clay that wanted hands. By the time the team reached the colossus vault, even the echo had learned to speak softly.
The gate they'd split with grammar in the last encounter stood open like a stubborn uncle pretending it had always intended to be generous. Beyond it, a cavern the size of a swallowed cathedral sloped into black, the floor patterned with plates of basalt that had flowed while the world was still making up its mind. Between plates, seams of iron winked like old stitches. At the far end, a ridge of stone ribs arced overhead, interlocking into a throat.
Luna crouched and put her ear to a seam. "It's humming," she said. "Not speech. Load."
"Music," Tam whispered, delighted. "Like a big drum under the floor."
Selene pinched a corner of predawn from her sleeve and fed it to a puddle; reflected dim light stitched a faint lane across the stone. "If it sings, we listen," she said. "And step where the song likes our weight."
Cyrus rolled his shoulders and paced, mapping stride to slab. The Oath cord across his chest settled as if approving of men who learn floors before they trust them. He set a hand to a column and leaned, feeling pressure push back. "It wants steadiness," he said. "Not heroics."
Aragorn walked to the edge of the ribbed throat and the bell warmed on his hip like a polite memory. Fire climbed his forearm in a thin, reading line; the white stitch under the black brand itched the way a healed cut itches before rain. He set his palm to a plate. The hum answered in the bones of his hand: push here, hold there, breathe.
"Terms," he said, voice level as a carpenter's. "We ask streets to hold until the last person passes. We ask stairs to warn before they fail. We ask ground to become a bridge when fear makes a hole."
Stone didn't thunder agreement. It sighed. The sigh moved through pillars and plates like an old house making up its mind to shelter one more night. Then, from the ribs, a sound rolled out at the edge of hearing—low, patient, round. It wasn't a word. It was a count.
"One," Selene murmured, recognizing the rhythm first. "Step."
They stepped—left foot, right—in time with the cavern's slow beat. The floor under their boots returned a deeper note, as if happy to feel honesty pass through it.
"Two," Luna said, quick mind riding slow tempo. "Hold."
They held, gathering weight over arches instead of edges. The seam at their feet brightened a shade, relief somebody finally read the manual.
"Three," Cyrus breathed. "Brace."
They braced, not the brittle stiffness panic likes, but the kind of readiness doors have when they prefer to be closed but might need to open. In the ribs overhead the count expanded into harmony as other chambers joined—deeper throats, lower halls—old stone adding its vote.
Tam started to grin. "I know this," he said. "It's the tune the city hums when people carry furniture."
"Furniture doesn't punish missed steps," Luna said dryly.
"Neither will this," Aragorn answered, hearing a promise in the third beat. "If we keep time."
The first test arrived without ceremony: a plate three spans ahead tilted, not to throw them, to ask whether they would crowd it. Selene lifted her hand and the shadow rope slithered three paces to the right, laying a lane across plates that wanted feet in a certain order. Cyrus moved first across it—not to prove strength, to show pace. Tam put his feet exactly where the rope told him because children are the bravest when given instructions with good verbs.
The tilt settled. A second test followed, meaner in construction: an invitingly straight run of basalt that would, two steps before the end, crack. Luna set a magnet at the seam with a small, almost affectionate click. "Warn before failing," she reminded, tracing the clause into iron. The seam shivered, confessed, and drew a hairline gleam ahead of schedule. They detoured without losing tempo.
At the third test, the ground withdrew a plate and left a chasm the size of a table—insulting for how dramatic it wanted to be. "Bridge," Aragorn said, palm to stone again, bell humming low. He felt the load ask for a counterforce and offered Earth's debt: hours of Civic Dusk, sore shoulders, ramps installed. The plate that was missing became a platitude the cavern had outgrown; the plates beside it widened a polite hand's breadth each, meeting in the middle like neighbors leaning from stoops to pass a basket.
Tam whooped and clapped once, the sound riding the cavern's note without breaking it. The ground did not smile; it had a job. It held.
They reached the ridge where the ribs narrowed into a neck. At its center a basalt choir sat like benches for giants, each slab tuned to a different tone by old pressure. Selene touched one with the back of her fingers and felt the note bloom up her arm—do, but older. Luna perched on another and hummed until it answered re, but stubborn. Cyrus leaned against a third; it did not sing; it vibrated until his bones remembered brace beat.
The audition lasted a quiet minute. When they were tuned, stone exhaled through the throat, and the choir sang—three notes, low, slower, lowest. It was not beautiful in the way songs are. It was beautiful in the way work is when it fits perfectly into the hands.
"Speak your clause," Luna said, as if to a clerk who had been waiting for the right file.
Aragorn set the bell on a rib and wrote into stone with heat that did not scorch, letters that would feel correct under boots: Hold while carried. Warn before failing. Fall after empty. He added a fourth for the city's bad days: Rise if a neighbor falls.
The choir sang the fourth back to him with a deep, reluctant kindness, like a father who has seen a boy try to lift too much and moves to the other side of the beam without sighing about it.
A tremor rolled through—heavy, honest. Overhead, rock dust ticked the stale air like a soft rain on metal. A slab at the edge of the chamber thought seriously about becoming a disaster and decided to become a bench instead. The ground at the plate they'd bridged earlier gave an experimental shrug and then settled into being a bridge permanently—a thin, excellent, reliable thing.
"Covenant accepted," Luna said, reading the way magnet needles steadied on her brass. She pulled a stub of chalk from behind her ear and scrawled in big letters at the throat where even fear would have time to notice: NOT FAST. The word glowed because simple truths do when everyone agrees.
"How we pay?" Cyrus asked, not because he wanted out, because he liked chore lists.
"With boredom," Selene answered. She stretched and made a face at her own shoulder, then smiled at it. "Carry planks. Teach footwork. Make people practice leaving slow."
Tam saluted gravely. "I can make a game out of that."
"You already did," Aragorn said.
They turned to go, and the cavern gave one last push—not a test, a gift. The floor beyond the throat rose by the thickness of a boot-sole, enough to meet a step that would have faltered. They did not applaud; they walked on it.
Back on the stair, the air cooled. At the mouth of the mine, dusk laid itself along the lane they'd promised, and the first Civic Dusk of the new covenant went to work. Chairs scraped into place; cups set down with names; a man at the end of a rope remembered without reason that he had been told today to rest, and to his surprise, found himself obeying.
"Report to the sky?" Luna asked as they emerged.
The Sunfall Commander watched from a parapet a block away, a courtroom that had put its wig down for supper. His eyes narrowed not in anger but in curiosity that had survived training. He lifted his spear an inch. "Proceed," he said, which sounded suspiciously like permission, and vanished with the good taste of a guest who knows when to leave.
Aragorn laid the bell on the parapet and listened to the city's pulse settle around the new clause. Health is seldom dramatic. It spread in the shape of people choosing where to put their feet.
Selene's shadow stretched itself across a cracked step and, finding no drama to drink, decided to be pretty instead. Cyrus sat deliberately, because walls that rest in public teach better than sermons. Tam drew a hopscotch that matched the cavern's three-beat count and labeled the squares Hold, Warn, Rise. Children learned it fast.
"Earth is on our side?" Tam asked, small voice asking a big thing.
"Earth is on its own side," Luna said, fond. "We're finally standing there too."
Aragorn felt the stitch under the brand ache once, then cool. The day owed him nothing; he owed the day nothing; they were even except for the ledger he had chosen to keep. He turned the bell until its hum matched the city's new tempo: work, pause, brace, breathe.
Down in the cavern, the basalt choir sang that same slow chord once more—do, re, brace—and the sound climbed the stair like bread smell climbing a tenement. The ground had decided to carry itself, with a little help.
— End of Episode 16 —
Key powers this episode: Earth covenant formalized (Hold while carried; Warn before failing; Fall after empty; Rise if a neighbor falls), Basalt choir tuning via three‑beat cadence, Shadow rope lane guidance, Oath pain‑split bracing practice, Magma Lance as stitch, mirror‑law clause inscribed in stone, Civic Dusk integration.
Next on Episode 17: Root Choir—Nexus practices leaving slowly while halos try to speed trials; a staged collapse chooses to wait; and the city learns a dance that makes stairs kinder than law.