Oceanographer Luke McAllister races to figure out why the ocean depth is changing off Florida's Treasure Coast. But before he and his crew discover what's transforming the deep, he stumbles upon an even greater mystery. Leagues below the waves, he swear he sees...a mermaid? Anya isn't allowed to get close to humans. But when a golden-haired researcher gets too close to her island, she can't afford to stay away. Together, this unlikely pair will seek to discover what's causing shifts in ocean floor. While their new alliance is forbidden, Anya will risk everything to save her beloved ocean. The only problem is, she's not sure what's really luring her in, her love of the sea or the tempest Luke has stirred in her heart. Either way, Anya knows that the dangers facing the sea are nothing compared to what will happen to her when her father learns she's broken the merfolks' most sacred law. Can Anya and Luke discover what lurks at the heart of the deep before it's too late?