Millennia ago, mankind fled the earth's surface into the bottomless depths of the darkest oceans. Shielded from a merciless sun's scorching radiation, the human race tried to stave off certain extinction by sending robotic probes far into the galaxy to search for a new home among the stars. Generations later, one family is about to be torn apart in a conflict that will usher in the final race to save humanity from a world beyond hope.