Seaborn (The Seaborn Series, #1)

All Life began in the ocean. The tides, the salt, the rolling waves are in our souls, and the sea will always have the power to call us home...

There's a world deep under the sea, a kingdom that has endured thousands of years without the modern world knowing it exists. Those who dwell there are thalassogenêis: seaborn. Kassandra is the king's granddaughter—the one he wishes he had killed when he'd had the chance. She comes from the sea, but she's spent her whole life in exile on the surface...