The day that Kai learns that he's half-human, half-merman and that he's the key to ending a 100-year-old war, is also the day that the entire ocean learns of his existence. For twenty-seven years his family had kept him hidden from the world, but now the strongest, most dangerous merman in all the seven seas knows about Kai, and he's coming to the surface for him.

To ensure victory, King Marius the Conqueror must capture the half-breed prince of Astria, his nation's greatest enemy, and claim him as his Mate in order to absorb his power before he learns to use it. There's only one problem: there's nothing Marius hates more than humans -not even an Astrian- and Kai is both those things. But when Marius sees the beautiful Kai and clashes swords with him, the cold-blooded king's blood begins to boil for the very first time. Perhaps he can tolerate Kai long enough to steal his power.

When a dark, handsome, sword-wielding stranger attacks Kai in his home only hours after discovering his heritage, instead of running, Kai fights even though he knows he's no match. Defeated, Kai is kidnapped to a world he never knew existed and is held prisoner against his will. Just when he thinks it can't possibly get any worse, the terrifying stranger informs him that they are to be wed.

"But I'm not gay!"

Thrust into a secret, dangerous aquatic world, Kai must learn to navigate swimming with a tail instead of legs and avoid a powerful, possessive king's advances if he wants to save his newly-discovered mer-people from annihilation.