Over 70 percent of Earth is covered in water, yet over 80 percent of that water remains unexplored. There are currently over 10 billion people on Earth, but terrestrial humans are only aware of those who live on land. The other three billion humans took a decidedly different evolutionary path, adapting to live in the largest combined area on the planet–the water.

These two highly-intelligent civilizations, while indistinguishable in their DNA, have adapted to the territories in which they live, and although they share a single planet, their worlds could not be more divergent. Kept apart by an oceanic demarcation line known as the Devine Gap, the oceanic difference in the depth to which a terrestrial human can dive, and that to which an aquatic human can ascend, the two civilizations have remained separated since their evolutionary births.

Following a chance encounter between Jacqueline, a terrestrial human and experienced dive master, and Argo, an aquatic human and scientific researcher, their desire to bridge the Devine Gap becomes an obsession for both of them. An obsession with potentially deadly consequences.

It has been said that the human spirit can overcome any obstacle, but can it overcome the water?