Mermaid princess Ylaine has only ever wanted one thing: her father’s recognition and approval. King Davor of Undersea, however, is obsessed with launching a war against the ignorant, pact-breaking humans. Ylaine believes that if she can convince her father that not all humans are evil, he might listen to her and call off his plans for war. Such a desire seems impossible, till the day she willingly trades a most precious gift to have the thing that she hopes will help broker peace between the realms: magic that transforms her into a human.
Safe in the palace of Overcliff, Prince Nathan seeks his own comfort, and dreads the day when the people of his failing kingdom will depend on him for their well-being. His father, King Theodore, remains distant and forgetful, while the Royal Council runs things—and as far as the Prince is concerned, he is free to continue doing as he likes. When a mysterious young woman arrives on the island, he begins to realize that all is not as it seems—and threats can come just as easily from across the sea as under it.