The two-hundred-and-ninety-pace air-flow chimney pipe was a narrow, square-cut stone crawlway, three feet wide and three feet high, angling upward at a steep twenty-degree slope through eighteen paces of dense granite to the outside gorge cliff. Kezra Venn and Yseld Arken reached the intake portal. Then, they found it choked solid with a plug of frost-shattered slate rubble, bird nests, and compacted ice that had piled up over half a century of disuse.
Worse still, at the far end of the eighteen-pace crawlway. There, the duct met the outer cliff face, an ancient outside iron louver grille had rusted into its stonework frame. Hundreds of years of wind-driven ice and rock-fall had jammed the heavy iron slats fully shut. That created a sealed plug that prevented a single breath of gorge air from entering the underground shaft.
“Clearing this from inside is impossible,” Yseld said, shining the narrow beam of her hand-lamp up the stone duct. “The scree is wedged tight against the rusted louver. If a crawler worms eighteen paces up that tube and starts prying at the rubble with an iron bar, the entire plug will slide down onto her head, choking her in three feet of loose slate.”
