The Third Book in the Wisteria Series by Bisi Leyton
Wisteria was forced to betray Bach in order to save his life. Two years later, his best friend and her blackmailer Enric shows up on the Isle of Smythe demanding she help the Family locate Bach's brother who has disappeared.
Dragged back into the center of the Family's politics, she searches for the missing Family member along with Bach who is still deeply bitter from her apparent callousness.
Traveling through the decaying human world, Wisteria and Bach uncover more truths about RZC Bio Technologies, Wisteria's complex family, Bach's mother and their seemingly impossible bond. And pay a very high price.