Under the Closed Sea

The guide crew followed a current beneath a sealed spillway and found markings carved into the submerged wall. They did not resemble language. Their spacing matched changes in pressure, as if the wall had been used to measure the movement of water rather than describe it.

At the deepest point, the crew heard a sequence of impacts from the other side of the stone. They answered once and received no second response.

The route map records depth only as below useful certainty. The crew declined to name the passage until they could return without making it a destination for everyone else.