Grieving for Luc, Natalie Pierce is forced by fate to once more come to the rescue of the human race. Her new aquatic adversaries are far more dangerous than anything she has ever encountered before and she needs all the assistance she can find to take them down. Nat must take steps she never thought were possible to combat the rising menace. Her conscience is torn between her personal morals and her role as Mortis. Her job is to safeguard the humans, but at what cost to herself?