Iionii (ee-oh-nee) is a water-alt—a genetically engineered human built for Haven's vast water district. Amphibious, sleek, and lethally graceful, she moves with lightning speed and swims like a creature born to the deep. She can love. She can dream. But like all altered humans, she is forbidden the one thing she desires most... a child.

In the depths of the Lake, she will make a discovery that will change the course of history in the subterranean world called Haven. Her discovery will change her too, but in ways no one could predict.