The first sign was a fish on the landing.
It lay in a handbreadth of water above the northern stair, silver belly flashing between two boots that had stopped together. Garn bent to pick it up. The fish twisted free of his fingers and vanished through the railing into darkness.
“That was the lower pond,” he said.
Ostel’s assistant was already running uphill with the bell. She struck three times, paused, then struck three again. Doors opened above the stair. A woman in an apron lifted a sleeping child against her shoulder without asking what the bell meant.
Iven looked down toward the pale roofs. A sheet of water had appeared across the outer shelf where they had walked that morning. Behind it, the sink’s northern wall shone in long, moving stripes.
They had spent six days below and around those roofs, measuring the separate passages that a flat map drew as one knot. The route back should have been a familiar climb. Now rain falling beyond their sight had found the natural seam Nyla had identified, and the stairs were becoming its outlet.
“Upper shelter,” Ostel said. “Everyone above the blue lintel. Bring drinking vessels, leave furniture.”
His voice carried properly. No one needed a stranger to explain their own flood bell.
