The slate that Eren had hung on the back kitchen wall was six feet wide and four feet high, salvaged from an old billiard table in the flooded basement of the Crown and Anchor tavern. Its surface was dark gray slate, smoothed by forty years of ivory balls, now framed in heavy ash timber and bolted directly into the granite stonework with four three-inch iron coach screws.
Pella stood before it with a stick of sharpened white chalk in one hand and a flat piece of dry felt in the other.
The room was quiet save for the steady drip of the back kitchen tap and the faint, dry click of the brass gear catch atop the courtesy arch on the bench behind her. Through the open door to the kitchen, the smell of Sister Merrow’s split-pea soup was beginning to thin out as the noon rush ended, replaced by the damp odor of scrubbed floorboards and cold river air.
Across the top of the slate, Pella had ruled twenty-nine columns, each marked with a small Roman numeral.
“Day One,” she said aloud, her voice small in the damp stone room. “Failed check. Surrendered student badge. Moved the arch from the college cellar.”
She drew a firm slanted line through column one.
“Day Two,” she continued. “First audio contact. Filed the iron billet. Checked the seven-two-pound payload rule.”
She slashed column two.
Beside the twenty-ninth column, she drew a heavy, jagged circle. She pressed the chalk so hard it screeched against the slate and snapped in her fingers. Inside the circle, she printed three words:
HOLLOW CROWN LOCK.
“Twenty-seven days,” Eren said from the doorway. He was carrying a wooden box filled with hand-forged iron wedges and a heavy cast-steel club hammer. “Sounds like plenty of time to build a wagon.”
“It’s not a wagon, Eren,” Pella said, picking up another piece of chalk from the trough. “Look at the numbers Ada left on her slate yesterday.”
She stepped to the left side of the board. There, she had copied the readings from Ada’s pressure test.
“Forty-two pounds of pressure,” Pella said, pointing to the chalked figure. “The normal pressure in a gravity-fed town baked-clay line is twelve. Fifteen during a spring high tide. At forty-two, the lime mortar between the pipe joints doesn’t just seep. It turns to porridge. The water forces its way between the bricks.”
“And if Sorell locks the Crown on Day Twenty-nine?” Eren asked, setting his tool box on the floor with a dull clatter.
“He isn’t just locking a gate,” Pella explained. She drew a diagram of the river’s three channels above the city. “He’s closing the natural mountain bypass. He’s forcing the entire flow of the Silt Reach through the Hollow Crown’s bronze drain tubes. To keep the High Terraces from feeling the back-pressure, his rig is already dumping fifty to eighty gallons a minute into the old abandoned upkeep channels under Lowbank.”
“Our larder wall,” Eren noted, nodding toward the back of the room.
“Our larder wall, the cellar under the Nine Lanterns, the foundations of the Ferry Museum. The lower vaults of Fish Street,” Pella said, her chalk tracing a widening web of lines that radiated through the lower district. “If he turns that key on Day Twenty-nine and seals the backup gates, the pressure in these dead trunks won’t stay at forty-two. It will spike past eighty.”
“And baked-clay doesn’t stretch,” Eren said quietly.
“Baked-clay shatters like an eggshell,” Pella said. “The entire sub-level will blow out from below. The foundations of the tenement houses along the quay will slide straight into the river muck. Not in three weeks. Within forty-eight hours of the lock.”
Eren walked over to the board, his heavy thumb tracing the jagged circle around Day Twenty-nine. His face was set in the hard, practical lines of a man who worked with wood that had to bear three tons of wet grain over rutted mountain roads.
“So why doesn’t someone tell the High Council?” he asked. “Councilman Vesk isn’t a fool. She understands property values, even if she doesn’t know a water gate from a breadboard.”
“Tell them with what?” Pella asked, turning to face him. “With my word? A failed third-year student who couldn’t keep a water-sprite in a clay pot jar? Sorell has twenty-four master summoners signing his reports, three hundred pages of gold-trimmed parchment filled with predictive differential formulas. A scale model that makes the High Council look like geniuses for approving his budget. If I walk into the Senate chamber with a piece of chalk and a broken pipe rim, the beadles will have me in the lunatic cells before I reach the second terrace.”
Eren picked up a piece of chalk, turned it in his fingers, and stepped to the board.
Beneath her diagram of the baked-clay pipe, he drew a small, crude picture of an oak wooden props wedge with an iron dog-pin through its heel.
“Then we don’t give them a theory,” he said. “We give them a ledger.”
Pella blinked. “A ledger?”
“Ada’s pressure gauge,” Eren said, tapping the slate. “You said she’s bringing another one today. A permanent one with a brass snubber that records the peak needle.”
“Yes.”
“Then we put that gauge on the pipe behind the larder,” Eren said. “We log the reading at six in the morning, at noon, and at six in the evening. Every single day. We log the river height at the ferry boat ramp on the same line. Sorell turns his little silver key up at the High Annex. Then, the needle will jump down here. When he opens a drain tube, the needle will drop. In ten days, we won’t have a student’s theory. We’ll have forty pages of stamped, dated, hands-on pressure readings that match his public operation log minute for minute.”
He picked up a string line weight from his pocket. Then he held it against the stonework frame of the board. The brass weight hung steady, plumb within a sixteenth of an inch.
“You can argue with a speech, Pella,” Eren said softly. “You can’t argue with a line weight. When a wall leans half an inch, no amount of Latin chanting will make it straight. If the gauge says forty-two pounds today and fifty pounds next Tuesday, the stone is breaking, whether Sorell likes it or not.”
Pella stared at the simple diagram of the wedge.
For five years, the college had taught her that power was a matter of ritual status. That if you wore the right stitched mantle, spoke the ancient High Lathmere vowels with the correct nasal rhythm. Then he carried an approved brass rod, the world would bow to your pronouncements. But Eren, who had never read a summoning grimoire in his life, looked at a town conspiracy the same way he looked at a sprung cart axle. Find where the load is binding, put a mark on the timber, and measure how far it bends under a ton of oats.
“An working ledger,” she murmured.
“An honest one,” Eren corrected. “Which means we don’t exaggerate the numbers to make him look worse. We don’t hide the spikes to make ourselves feel better. If the pipe is holding at forty-two, we write forty-two. If it jumps to fifty, we write fifty. And when we have enough lines on the slate, we show it to someone who has to pay the repair bill.”
Eren took a small wooden mallet from his tool kit. Then it knelt on the flat stone slabs near the back kitchen drainage grate. He tapped the four corner stones in a slow, rhythmic circle: tock... Tock... Clonk... Tock.
On the third stone, the pitch dropped from a solid, high-hum ring to a dull, hollow thud that sounded like a wooden cask half-filled with wet sand.
“There,” Eren said, pointing with the mallet head. “That stone has lost its bedding. The river silt beneath the floor is washing out toward the old under-road drain. In three weeks, that flat stone slab will drop two inches under a heavy boot.”
Pella knelt beside him, placing her fingers along the mortar joint. The lime was fully gone, replaced by a greasy gray paste of wet river clay and black coal grit.
“The whole back kitchen is tilting toward the larder,” she noted.
“Half an inch in ten feet,” Eren confirmed. He pulled his brass folding rule from his bib and measuring the step. “The old toll tower was built on timber wooden support posts driven sixty feet into the river gravel. The wooden support posts are sound enough as long as they stay wet and cold. But if Sorell pumps warm stone water through the ground around them, the timber rots three times faster. In six months of warm slow leak, an oak pile turns into black peat that you can gouge out with a wooden spoon.”
Pella stood up, looking back at the six-foot slate on the wall. She picked up a piece of red chalk and ruled a level dividing line beneath her Day Twenty-nine marker.
“Then we add a second ledger,” she said.
“What kind of ledger?”
“A settlement ledger,” Pella answered, printing the words across the bottom of the slate. “Every morning, before Merrow lights the soup kettles, we measure the drop of that flat stone slab against the door doorstep with your brass rule. We measure the heat of the water coming out of the back kitchen pump. We log both numbers in red chalk right under Ada’s pressure readings.”
Eren looked at the board, then gave a slow, single nod of his head.
“Good,” he said. “A carpenter understands settlement. If you tell a town judge that magic is unbalanced, he falls asleep. If you show him that a public building is dropping an eighth of an inch a week toward the canal, he sends a checker with a notebook. Now give me that cold chisel. We have three courses of limestone to take out before Ada’s tea break.”
He picked up his club hammer and handed her a four-inch cold chisel from the box.
“Come on,” he said, nodding toward the dark recess behind the larder shelves. “Ada’s lunch break is in twenty minutes. If we don’t have that first stone out of the wall before her hoop rings, she’ll spend her entire twenty-four minutes telling us we don’t know how to swing a hammer.”