The water tank vault beneath Tier Four was a huge, underground pool built by the First Epoch stonemasons, hollowed out of black fiery dark rock rather than the porous white limestone above.
A foot of stale, stone-heavy water covered the flat stone slabs, rippling with rainbow-bright slicks of rendered animal fat, coal soot, and stopped potash lye. Overhead, massive groined vaults rose fifty feet into the damp gloom, supported by eight-sided stone pillars twelve feet thick. Each pillar was carved with ancient water-drainage calibrations. Notches and numbers carved in an ancient script that looked like careful punctuation glyphs. It measured the flood levels of forgotten hundreds of years.
Ren Vale stood knee-deep in the cold water, his lambskin apron soaked to the waist, his left arm supporting Mira as she caught her breath against the base of a central pillar.
His lungs burned with the residue of sulfur smoke, and his throat was raw. But he kept his boots planted firmly against the slippery underwater stones. Beside him, Mira leaned her head against his shoulder. Her right arm lay motionless across her chest, the smoky many-sided quartz glowing with faint, rhythmic pulses of violet light as it answered the underground hum of the bedrock. Her breathing had grown shallower during the sprint from the vats, each breath in chiming with the clear, high ring of a struck tuning fork.
