Ursula Violet Kronborg might be a princess, but she feels more like a prisoner. Ever since her parents died in a shipwreck two years ago, she can't help but wonder if the rumors surrounding her family are true. Are they really cursed? After all, her cousin Tristan never fully recovered from the plague that swept through Elsinore. Her grandfather, King Eric Kronborg, seems to be getting more paranoid by the day. And after the incident on her last birthday, it's no secret the entirety of Elsinore thinks she's some sort of witch. Accidentally unleashing powers she didn't know she had, Tristan disappears-and her life is turned upside-down. To rescue her cousin, she accepts the help of a mysterious sea witch named Hydra and sets off on her adventure. Her journey tests her in ways she never imagined. She will stop at nothing to save her cousin. Secrets come to light and she quickly learns that there's more to Hydra-and her own family-than meets the eye. Rescuing Tristan means waking up a long-dormant evil in the deepest part of the ocean. Now Violet must learn the full extent of her powers before the most feared sea serpent of all time destroys her family, her home...and herself.