Seventeen-year-old Florence Waverley is out of her depth. Literally. Kidnapped and taken below the waves to the mer world of Niemela, she is the ultimate gift for merman Prince Kiren: a human familiar tied to his side. But nothing is what it seems amid the beauty and danger of a dark ocean.
Every Niemelan has a role to play, from the mermaids who weave towers out of kelp to the warriors who fight sea monsters. But in trying to survive, Florence will end up in the middle of a war between the mer and the Darkness. A conflict that will push her between two brothers: Kiren, the charmer inexplicably drawn to both her and the monsters; and Rolan, the loner who has been pushing her away since the day they met. But in order to take a stand–and find out where she belongs–Florence will have to risk it all: her life, her heart… and her very soul.