The limestone question was still turning over in his mind when a new sound reached them.
It came from the northeast. A steady percussion, low and heavy. Each impact followed the last with the same rhythm, regular enough that the pattern became obvious after three strikes. Beorn listened and measured it against sounds he already knew.
Then he stopped.
Around them the street reacted at once.
A woman selling flatbread from a board balanced across two barrels turned toward the northeast. Without looking at anyone else, she slid the board back against the wall behind her and secured her goods.
A man guiding a loaded cart pulled the reins tight. He studied the same direction for a moment, then steered the cart into a narrow space between two buildings and left it there.
At the edge of the street, two children leaned out from a doorway to look. An arm reached from inside and pulled them back without a word. The door shut.
The response carried the ease of repetition. These people had heard this before. Every one of them already knew what came next.
"Northeast wall," Godric said.
Beorn was already moving.
The street leading toward the miners' quarter was wide enough for the formation to keep pace. Beorn remembered this stretch from his earlier walk.
Low rows of patched buildings lined the road. Workers stood outside them with tools kept sharp and maintained even though the mines themselves were silent. The trade had survived even after the work had not.
At the outer edge of the quarter stood the section of wall Beorn had marked earlier as the worst in the city. Timber braces supported the upper courses where the stone had begun to fail.
The mortar between the joints looked dry and pale. Thin seams of old work, first done poorly and later patched with even less care.
The sound deepened as they drew closer. Near enough now that each impact traveled through the ground before it reached the ear. Beorn felt the vibration through the soles of his boots a moment before the next strike landed.
The wall came fully into view at the end of the road.
Two of Coss's men were already descending the parapet steps as Beorn's group arrived, moving quickly into position at street level. A third remained above, directing the others down.
The men spread along the base of the wall with crossbows raised. Fast, efficient movement. A routine they had carried out before.
Four crown garrison soldiers stood near the bottom of the steps. Their spears rested loosely across their bodies, neither raised nor lowered.
One glanced at Beorn, then at Godric, then toward the men taking control of the stairs. He leaned toward the soldier beside him and muttered something too low to carry.
Two drifted away from the steps without any clear purpose. The other two followed. All four kept well back from the wall.
One of Coss's men stepped in front of Beorn and raised a hand.
"The wall's already covered, my lord. We've got the defense handled."
Beorn lifted the signet ring where the man could see it and kept walking.
The man hesitated, hand still half-raised. Then he stepped aside.
From the top of the wall the situation became clear.
Below the parapet, pressed against the northeastern face, clustered nearly twenty monsters. The number shifted as bodies shoved and climbed over one another at the edges, but the mass stayed packed against the base of the wall.
A fragment of memory surfaced. Greybacks.
They were larger than the name suggested. The shape of a boar still showed beneath the changes, but generations in the wilderness had twisted the species into something harder and uglier.
The bodies carried most of their mass forward, thick through the shoulders and neck. The head sat low while the hindquarters drove the animal ahead with brutal force.
Along the spine and across the shoulders, natural hide had given way to ridged plates of mineralized growth. Dull grey-white slabs overlapped one another from behind the skull halfway down the back like stone forcing its way through flesh.
Midday light struck those plates and died there.
Between the larger sections, patches of dark hide still showed through. Scar tissue ran around the seams where the growth had split and hardened over older wounds.
Their tusks were shorter than a true boar's but thicker, built for smashing.
Each animal hurled the reinforced front of its skull and shoulders against the weakest part of the wall.
The impacts were dull and violent. Stone trembled. Dust spilled from the joints with every strike. One beast hit hard enough that its forelegs folded beneath it before it snorted blood from its nose and drove itself forward again.
Movement caught the edge of Beorn's vision.
He glanced sideways.
Aestrith stood beside the parapet with both hands flat against the stone, eyes fixed on the animals below.
Beorn noted the posture, then turned back to the wall.
Coss's men fired the first volley in two waves. The front line aimed at the leading animals to draw attention. The second fired into the packed cluster while the front ranks were still reacting.
Crossbow bolts struck the mineral plates with a hard crack. Several skipped away immediately, thrown off by the angle.
Others punched into softer gaps.
One Greyback screamed when a bolt buried itself beneath its jaw. Blood sprayed across the stones as the animal twisted sideways into another beast.
A second took a bolt deep behind the foreleg and collapsed to one knee beneath the crush of bodies around it.
Another volley followed. Then another.
The parapet filled with the snap of crossbows, shouted reloads, boots scraping against stone.
Bolts hammered into the mass below.
One Greyback reeled backward with a bolt jutting from its eye socket and slammed into two others behind it hard enough to knock all three sideways.
Another managed only a few staggering steps after a bolt punched through its throat. Blood poured down its chest in heavy pulses before its legs failed beneath it.
The pressure against the wall finally broke.
The monsters recoiled unevenly. Some spun in place. Others shoved through the pack trying to flee first.
The retreat turned savage almost immediately.
Panicked bodies crashed shoulder-first into one another. Tusks ripped open flanks at close range. One wounded Greyback slipped in blood near the wall and vanished beneath the others as they trampled over it in their rush to escape.
The tight cluster dissolved into chaos.
Several animals bolted left. Others broke right. One slammed directly into the wall before wheeling away again, leaving a dark streak smeared across the stone.
Another collapsed less than fifty yards from the wall, kicking violently in the dirt while blood spilled from its mouth.
The remaining Greybacks withdrew roughly a hundred yards before stopping, scattered now instead of packed together. Several limped. One dragged a ruined hind leg behind it.
At the top of the steps, Coss's officer barked a short order to the dozen men still on the parapet. They kept their crossbows trained outward.
Beorn began walking the length of the wall.
One hand rested against the parapet as he leaned outward to inspect the stone below.
The vertical crack he had noticed earlier stretched farther than he had first estimated. From this height he could follow it all the way to the base course, where it widened into a pale split between stones that had begun to separate.
Along the lower courses the mortar had crumbled into powder in several places. The binding material had failed entirely, leaving loose grit packed into the joints with nothing securing it.
He moved farther along.
The next section held better. The mortar was old but still firm. The stones sat tight against one another.
Then he reached the bend where the wall curved with the terrain.
The construction changed there.
The stone was older, cut differently. Another mason's work from another generation.
The seam between the two phases ran directly through the curve, and it formed the weakest line in the entire stretch. Years of heat, cold, and water had shifted the materials apart little by little.
Beorn stopped.
Then he reached into his coat and removed the ledger.
The quarry route sketch he had drawn earlier occupied the right margin of the page, the line extending north toward the limestone deposits. The question mark at the source still waited unresolved.
He turned the book sideways and began adding new marks beside it.
The crack. The failed mortar. The seam between the two sections of construction. The places where the Greybacks had concentrated their pressure.
The sketch filled the margin quickly, each inch of the page carrying denser detail than his usual notes during negotiations or planning.
His hand placed every line carefully, preserving the proportions even at the reduced scale.
"How often," he said without looking up.
Godric stepped beside him. "Attacks like this on this face? About thirty in the last year. Ten the year before that."
Beorn kept writing.
"There used to be whole seasons where nothing reached the walls," Godric said. "The last couple of years changed that. It started increasing about a decade ago and never slowed down."
"What changed?"
Godric looked out over the barren ground beyond the wall where the Greybacks lay scattered.
"No one knows. Something changed in the wilderness."
The timing might matter. It might not. There still wasn't enough information to know whether the two facts connected.
Beorn wrote the numbers in the margin. Thirty attacks in the last year. Ten the year before. He drew a short line beneath them and left space to continue the record later.
"There's another section that's worse," Godric said.
Beorn looked up.
Godric pointed farther along the northeastern wall beyond the bend.
At the far end of the visible stretch, dark staining climbed the lower stone. Water seepage. Long enough and frequent enough that the moisture had bled through to the outer face.
Beorn studied it for a moment.
Then he closed the ledger without finishing the final line.