Air Conduit Beta was an upright air-flow shaft four arm-lengths square that dropped eighty deep-water lengths through the double hull of the Ark.
Cut from solid blocks of glassy dark rock and lined with rusting-resistant lead sheeting, the channel had been designed to draw cold air from the outer oceanic fissures and circulate it through the lower fire rooms that powered the Ark’s heat ballast pumps. In the dry season, the draft was a gentle, freezing breeze that smelled of clean sea-salt. But in times of clockwork purge, the channel served as the main exhaust chimney pipe for the underground steam-boilers situated eight leagues below the keel.
Fourteen elite hired blades from the Azure Firmament Sect’s Iron Vanguard were crawling upward through the shaft.
They had realized that the main avenues were death-traps, blocked by fallen portcullises and flooded with magnetic iron mud. Seeking to bypass the defenses, their squad-leader—a veteran sapper named Gou who carried a pair of iron-toothed climbing crampons on his hands—had discovered the lower intake grate of Air Conduit Beta.
“Keep climbing!” Gou hissed down the shaft, his voice echoing in the upright chimney pipe. “The land-mapper is watching the main hall! We come out behind his position in Entry hall 538 and take him in the rear! Drive your iron picks deep into the lead joints!”
