When the Imagine Network commissioned a documentary on mermaids, to be filmed from the cruise ship Atargatis, they expected what they had always received before: an assortment of eyewitness reports that proved nothing, some footage that proved even less, and the kind of ratings that only came from peddling imaginary creatures to the masses. They didn't expect actual mermaids. They certainly didn't expect those mermaids to have teeth. This is the story of the Atargatis, lost at sea with all hands. Some have called it a hoax; others have called it a maritime tragedy. Whatever the truth may be, it will only be found below the bathypelagic zone in the Mariana Trench…and the depths are very good at keeping secrets.

Seven years ago, the Atargatis set off on a voyage to the Mariana Trench to film a “mockumentary” bringing to life ancient sea creatures of legend. It was lost at sea with all hands. Some have called it a hoax; others have called it a maritime tragedy. Now, a new crew has been assembled. But this time they’re not out to entertain. Some seek to validate their life’s work. Some seek the greatest hunt of all. Some seek the truth. But for the ambitious young scientist Victoria Stewart this is a voyage to uncover the fate of the sister she lost. Whatever the truth may be, it will only be found below the waves. But the secrets of the deep come with a price.