The shift from the howling gale of the castle walls to the enclosed silence of the eastern air-flow stair was immediate and heavy. Kezra Venn stepped past the granite doorframe of the turret. Then, the roar of the mountain wind was cut off as though an iron drop-gate had slammed shut, replaced by the damp, sound hollow of an ancient upright shaft. The air smelled of cold limestone dust, rotten-egg hard coal soot that had drifted down from the surface chimneys for a hundred years, and the faint, sweet chill of underground slow leak.
The stairway was carved as a square helix hugging the outer boundary of the Stonewake mountain prism. Unlike the hurried, roughly timbered stone drifts Kezra had explored in the western mines, this shaft was a royal building monument from two hundred years earlier. The survey corps had quarried the spiral directly from the living stone. Twenty-pace flights of square-cut steps dropping at a steep thirty-degree pitch. It ended at vaulted stonework landings where the stairway turned ninety degrees to follow the next face of the square. Each flight was four feet wide. It was flanked on the inner wall by a handrail channel chiseled directly into the rock.
