As people close to Juliet fall victim to a murderer who leaves a macabre calling card of three clawlike slashes, Juliet fears one of her father's creations may have also made it off the island. She's determined to find the killer, though it means awakening sides of herself she had thought long banished, and facing loves from her past she never expected to see again. And as Juliet strives to uncover the truth while searching for a serum to cure her own worsening illness, she finds herself once more in a world of scandal and danger.

With inspiration from Robert Louis Stevenson's The Strange Case of Dr. Jekyll and Mr. Hyde, this is a tantalizing mystery about the hidden natures of those we love and how far we'll go to save them from themselves.