The sky vault of Entry hall 315 was dying from the ceiling downward.
In the ancient water-mapping charts preserved upon the cured sharkskin scrolls of the lower archive, this chamber was named the Grand Pillar hall of the Celestial Columns. Eighty massive pillars of rose-veined granite, each eight paces thick and eighty arm-lengths tall, rose in double rows of stone pillars to support a huge barrel vault. Embedded into the dark stone of the ceiling were twelve thousand soft glow-stone studs, arranged in the precise sky-high map points of the pre-flood sky. For ten thousand years, the cold blue light from those sky studs had lit up the dark water of the half-tide, guiding the quiet movements of the Mapmaker across the deep basins.
Now, as Qiao Ming and Yan Zhiqiu crossed the northern threshold, half of the stars were already gone.
They hadn’t faded or burned out from natural age. They were being smothered under a writhing blanket of grey hard shell three inches deep. A high-pitched, metal roar—like the sound of ten thousand scythes cutting through dry wheat—filled the upper reaches of the vault. It shook through the solid granite pillars until the flat stone slabs beneath Qiao Ming’s bare feet shuddered with nonstop, clashing tremors.
