The awakening of the Great Clepsydra was not merely a ritual triumph. It was the clockwork key that unlocked the high-pressure automation of the entire Fifth Century.
The second sky-high plate completed its first quarter-division of rotation. Then, a bronze tripping-pin set into the rim of the lunar colure engaged a backup release lever on the tower’s southern pier.
CLACK.
High above in the ceiling chimney pipes, an ancient high-pressure valve opened.
Twenty arm-lengths away, through the southern archway that connected the clock tower to Entry hall 448, a deep, earth-shaking rumble erupted from within the floor flags. The sound of three thousand years of trapped underground pressure finding its release.
Qiao Ming and Yan Zhiqiu sprinted down the spiral stairs, their bare feet flying over the iron steps, and rushed through the portal into the Great Silt Basin.
Entry hall 448 was a huge tiered arena seventy arm-lengths in width, surrounded by five nested tiers of stone seating carved from dark green chlorite. In the center of the arena lay the basin: a circular depression four arm-lengths deep and forty paces across, lined with polished slabs of white Carrara marble.
For over thirty hundred years, this basin had served as the dead-water trap for the sector. It was choked with one hundred and twenty tons of heavy, hardened black silt. A dense, foul-smelling deposit of interstellar mud and dried halite crust that had piled up three feet deep, burying the central floor fully.
