Ava is part of Humanity's last, desperate attempt to save itself from an alien enemy. Six small ships with three hundred survivors between them set out for the closest refuge. Their destination is The Shattered World, an oceanic planet that only just makes it onto the lowest level of the Possibly Habitable Index. Earth's gone, so Humanity's remnants have to do their best with what they have. But humans are not designed to live in a world that's 90% water, so drastic measures have to be taken. Over the course of the flight, Ava and nearly two hundred other volunteers have been genetically reconstructed, and on the eve of their arrival upon The Shattered World, their metamorphosis is complete. The experiment was harrowing, and many lives were lost, but Ava survived. Now, she's the next step in human evolution, one equipped to deal with a watery planet. Still, the future is uncertain for Ava and the other genetically-engineered merfolk. The Shattered World holds many dangers and many secrets and, looming over every moment, there's the ever-present threat that the Earth-Destroyers will find them.