Night on the seam smelled of salt and old paper: a thin, sharp cold that made breath visible and made the city's edges feel brittle. The seam itself was a scar in the Bonebridge's underbelly, a place where the archive's rails met the city's forgotten conduits and where, if you listened close enough, you could hear the ledger's margins whisper. Aria crouched in the shadow of a maintenance arch, the lead-lined case at her knee and the manifest folded into the small of her back. Lantern light pooled in the corridor like small moons; beyond it, the harbor breathed slow and indifferent.
Halv's rope was coiled over her shoulder, a familiar weight. Rell checked the tracer's lattice one last time, fingers moving with the quiet certainty of a man who read machines the way others read faces. Luna stood a little back, hands folded, the jasmine at her throat a private weather. The apprentices clustered behind them, faces pale and determined; they had been given small tasks—watch the far mouth, hold the false exits, keep the market's gossip from turning into a blade.
They had come for a seam: a seam the treatise's marginalia had hinted at, a place where a keeper's registry had been folded into a donor manifest and then hidden in a vault's moving cart. If the Spiral's keepers had been real, if names had been offered as counterweights, then seams were the places where the ledger's architecture showed its stitches. Tonight they would pry one open.
"Two minutes," Halv murmured. Her voice was a thread. "Platform swap at the kink. We get in, we get the registry imprint, we get out. No heroics."
Aria's fingers closed on the hilt at her hip. The Tidebind aftershock from the Bastion still sat in her muscles like a bruise; her hands were steadier than they felt. She had learned to carry costs like tools—count them, account for them, make sure they did not fall on one person alone. Tonight the cost would be different. Tonight they would need a living diversion.
The Night Orchard answered in the way it always did: not with a shout but with a rustle. Thornkin were not beasts so much as bargains—braided briar and living rope that answered a call if you fed it what it wanted. They could tangle a launch's propeller, hold a gate's hinges, or wrap a siege engine in thorns until men hacked at their own hands. But Thornkin did not work for coin. They worked for names and offerings, for fruit and song and the small, private things people were willing to give. The bargain was explicit: the Thornkin took what you offered and did what you asked. The ledger's arithmetic had a place for such trades.
Luna stepped forward then, the apprentices parting like reeds. She carried a small silver plate in both hands; on it lay a single thing wrapped in oilcloth—a child's ribbon, faded and frayed, the color of lemon peel. Aria recognized it at once: a ribbon Aria had seen once in a market stall years ago, the kind a mother tied into a child's hair. It was not Aria's ribbon; it belonged to someone else, a small, private thing they had been given by a witness in exchange for protection. The ribbon had been kept in the Loom's stores like a talisman.
"We call them with an offering," Luna said, voice low. "They will take a memory if we ask. They will not bargain for less. They will not be fooled."
Aria's throat tightened. Thornkin bargains were blunt and honest; they did not pretend to be anything else. The cost would be immediate and personal: a cherished memory offered up and taken, folded into the Thornkin's hunger. The memory would be gone from the giver's mind as if it had never been. It would leave a hollow that could not be catalogued. They had used Thornkin before for small things—tangles at a launch, a briar to snag a rope—but never for a seam this delicate.
"Who will give it?" Halv asked, voice careful.
Luna's eyes met Aria's. For a moment the night held its breath. Aria felt the ledger's thread tighten in her chest like a rope. She had already paid a cost in the vault—something small and private had been taken from her there—and the memory's absence sat like a coin she could not find. She had learned to count losses and to keep them from being the only thing anyone carried. But the seam tonight would be a hinge; if they failed, the registry imprint would be lost and the donor line would curl away.
"I will," Aria said.
The words left her like a small, fierce thing. She had not expected to volunteer; she had expected to bargain. But the Loom's work had taught her that some debts were not meant to be passed on. She reached for the oilcloth and unwrapped the ribbon with hands that did not tremble. The ribbon smelled faintly of lemon and of a child's hair oil; it was a small, private thing that had been kept safe for reasons that were not entirely practical. Aria held it up to the brazier's light and felt the memory of a kitchen table—warm wood, a chipped bowl, a small hand reaching for bread—rise like a tide behind her eyes.
Luna's fingers closed around the ribbon and she hummed a cadence that braided the Night Orchard's appetite into the room. The Thornkin's response was not immediate; it was a slow, living thing that answered in the dark with a rustle like wind through brambles. From the seam's mouth a limb uncoiled—black briar and living rope—and it curled toward the silver plate like a hand reaching for a coin. The Thornkin's thorns glinted in the lantern light; their sap smelled of rain.
"You sure?" Halv asked, voice small.
Aria nodded. The memory she would offer was not a ledger entry or a witness's name; it was a private thing she had kept in the hollow of her chest, a small domestic image that had kept her human through raids and nights. She had already felt a name slip in the vault; she had learned the ledger's arithmetic in the hard way. If giving this memory meant the seam would open and a keeper's registry could be read, then she would pay it.
Luna set the ribbon on the silver plate and the Thornkin's limb closed around it with a sound like a lock. The briar's thorns pricked Luna's fingers and a sap-smell rose. Luna's cadence braided the Thornkin's appetite into a net and the offering was taken. For a heartbeat nothing happened. Then the Thornkin's limb tightened and the ribbon vanished into the living rope as if swallowed by a mouth.
Aria felt it like a small, clean cut. The memory—warm wood, chipped bowl, small hand—slid away from her mind as if someone had turned a page and removed a paragraph. It left a hollow that made her chest ache. She staggered, surprised by the sudden absence of something she had not known she was carrying. The seam's air tasted of sap and lemon and the ledger's cost.
"Anchor," Luna said, voice steady. She wrapped a teacher's hum around Aria like a hand and steadied her. "You gave it willingly. That matters."
Aria swallowed. The hollow where the memory had been felt like a coin she could not find, but the seam's mouth had opened. Rell's tracer hummed as he fed the filament into the seam's edge; the lattice crawled along the metal and teased out a faint registry imprint that had been folded into a crate's seam. The tracer translated pressure into a ghostly image on its glass face: a spiral, a dot, a registry number half-visible beneath a smear of wax.
"Got it," Rell said, voice tight. "Registry imprint—Virelle trust line. It's faint, but it's there."
They moved fast. Halv slipped into the seam's throat with the practiced certainty of someone who had learned to make a building tell its secrets. Apprentices formed a screen at the mouth and kept watch for the vault's watchmen. The Thornkin's limb uncoiled and braided itself into the seam's outer rail, tangling a maintenance cart's wheel and holding it like a child's hand. The diversion worked with the blunt honesty of a bargain kept: a launch's propeller snagged, a cart's wheel jammed, men cursed and hacked at living rope that would not be cut cleanly.
Rell fed the tracer's readout into the Loom's ledger and Halv wrapped the registry imprint in oilcloth. The seam's mouth closed behind them like a wound stitched, and the Thornkin's limb withdrew into the Night Orchard with a rustle that sounded like a satisfied sigh. The offering had been taken; the Thornkin had done its work.
They did not celebrate. The cost was still a raw place inside Aria, a hollow where a small domestic memory had been. She had given it willingly, and that made the ledger's arithmetic less bitter, but it did not make the absence any easier to carry. Luna's hand found hers and squeezed, fingers warm and steady.
"You did what you had to," Luna said, voice low. "We have the imprint. We have a line."
Aria let herself lean into the touch. The tracer's lattice hummed on the table like a small, patient animal. The registry imprint was a map: Virelle, trust line, Salted Bastion vault. The seam had yielded a thread they could follow.
Outside, the harbor's night was indifferent. The Thornkin's sap still clung to Halv's gloves and the apprentices' faces were pale with the strain of the raid. They moved like a tide through the Bonebridge's underbelly, careful and deliberate, carrying the registry imprint and the knowledge that a name had been paid for the seam's opening.
On the skiff back to the Loom's safehouse, Aria sat with her hands folded and felt the hollow where the memory had been like a small, private wound. She could not call the kitchen table's chipped bowl; she could not summon the small hand that had reached for bread. The ledger had taken a coin she had not expected to spend.
Luna sat beside her and hummed a small cadence that smelled faintly of jasmine and rain. "It will come back," she said, though her voice did not promise certainty. "Memories shift. Sometimes they return in fragments. Sometimes they don't. But you gave it for a reason."
Aria closed her eyes and let the night hold her like a promise and a threat. The seam had yielded a registry imprint and a line to a patron house; the ledger's thread had been pulled taut. They would follow it to the Salted Bastion and beyond, and they would count the cost of every step.
For now, the Thornkin's bargain had been kept. A cherished memory had been offered and taken. The seam had opened and closed. The Loom had a map, and the city's margins had been pried a little wider.