The entrance to Entry hall 421 was marked by a dramatic change in both the scale of the stonework and the composition of the air.
Here, the smooth, decorative stone retaining walls of Parian marble and purple red stone that had lined the last galleries gave way to raw, plain blocks of dense cast iron and magnetic hard black rock. The hall was narrow—barely four paces from wall to wall—with a ceiling that plunged to fifteen feet. That created an oppressive, tunnel-like enclosure designed to compress invading forces into an indefensible file.
Every surface was cold to the touch, chilled by the huge heat mass of forty thousand tons of solid iron plates embedded within the stonework.
Qiao Ming walked three paces ahead, his bare calloused feet moving with deliberate, rhythmic care across the iron-plated floor flags. The plates were diamond-patterned to provide traction for heavy boots. But hundreds of years of condensed maritime fog had coated the grooves in a thin, greasy glaze of rusted fish oil and green rust. His toes gripped the raised ridges with automatic, feline balance, testing each plate for loose rivets or underground voids before committing his full weight.
Behind him, Yan Zhiqiu stepped softly, her recurve bow unstrung and slung across her back, her left hand resting lightly on the sealskin case that protected the Broken Slate against her ribs.
