Wars and ecological destruction have forced the human race to abandon the surface of the planet and take refuge underwater. Now, hundreds of years after the creation of their vast domed cities and subterranean tunnel networks - aptly named Oceania - scientific advances have moved them forward and created a better society - or so they think.

Argent - one of the ‘scientific advances’ - is a Merran, genetically modified from birth to be amphibious and trained from childhood with his many peers to repair and expand Oceania, and to rescue citizens in emergencies. When his best friend Luna goes missing during a routine training exercise and the government that made them turns its back on her, he goes to the only other people under the ocean who seem to care. Soon he is entangled in an intrigue that could cost him everything he has ever known. He is inextricably bound to Oceania, but his new friends have shown him a different path. In the end, will Argent follow his bond to Oceania or to his instinctual draw to the truth of his world? Will he succumb to his fate, or make his own?