When FBI agent Aaron Hotchner falls into a storm-tossed ocean, his life is saved by a mysterious girl who disappears before he can truly see her. Rosalie is a mermaid princess with powers tied to the sea itself, bound by ancient rules that forbid her from revealing her world to humans. Yet something about Aaron draws her closer, until curiosity turns into something far more dangerous. Because when the ocean calls and hearts collide, even the strongest tides can’t keep two worlds apart.