The gray wash of dawn came through the high, barred window of Sister Merrow’s kitchen back kitchen, cutting across the stone floor in narrow, dust-mote ribbons. The room smelled of wet limestone mortar, stale pine grease. The sharp, sour tang of vinegar wash that Merrow had used to scrub the soot from the wall tiles three hours earlier.
Pella Rook sat on an overturned ash timber crate, her elbows propped on her knees and her cart driver boots flat against the damp flat stone slabs. Her wool apprentice tunic, patched at the elbows with greased pigskin, still carried the faint, scorched odor of stone steam. Her palms were stained gray from scrubbing the chalk boundary ring until her fingers were raw, but the faint copper green rust on the edges of the brass arch wouldn’t come off. The arch stood against the far stonework, its curved members cold to the touch, its open-circuit runes dormant and dark.
There was no sound in the alleyway outside except the distant, rhythmic clack of the Lowbank ferry chain grinding over its timber gallows and the dull suck of the river tide pulling against the stone quay.
Beside her feet lay the wooden toolbox she had carried from the Ferry Museum cellar. A battered pine tray containing two cold chisels, a brass-headed drift punch, an oilcan filled with rancid lard-oil, and Ada’s spare three-quarter-inch box wrench, forgotten on the flags. Just then, the steam blew. Pella reached down and turned the wrench over. The…


