While fighting for their lives, they must battle dark and forbidden desires hidden in the ocean's depths...

After defeating the covert agency that threatened to destroy her and her sisters, Addison Lonike grudgingly resumes her life as an EMT in Maine. She would love nothing more than to take on the dangerous Mer queen, Magaera, who is hell-bent on destroying them. But with two baby nieces on the way, she can't take the risk—that is, until Mason McKenzie arrives.

Captain of the naval task force on the hunt for Queen Magaera in the Mediterranean, Mason sees the perfect recruit in Addison. But while at sea, the pair is pulled under a wave of passion that threatens their independent natures—and their mission. An encounter with a new race of male sea-shifters further complicates Addison's desires. Now, she must choose between a life of the sea or fulfilling the deepest longings of her heart...