Death, power, transformation.... When Nessa's dad dies, the last thing she's expecting is to lose everything else too. But when her hair suddenly turns electric red, and her estranged grandma turns up on her doorstep ready to haul her off to an isolated island, that's exactly what happens. In one day, Nessa losses her mother and her friends, and learns that she's a redheaded sea-witch with magical powers. She's one of many Neptunians - magical beings blessed by the sea - which includes selkies, mermaids, and sea nymphs. Nessa doesn't want to live on an island, she doesn't want to be a sea-witch, and she certainly doesn't want to be hunted by humans who harvest Neptunians for their magical powers. But if Nessa wants to live, she'll have to accept her new life and everything that comes with it, including a witty pirate named Caesar, who just might break her heart.