She's not supposed to exist… They're only stories. But there's something in the water. In the time before man, there were others. Perfect beings of the earth, water, air, and fire. The world was theirs during the unrecorded time. And for a while, there was peace. To Cora of The Shallows, Princess of the Undine Water Fae and Captain of The Queen's Guard, humans have been the enemy ever since the Elementals were banished from The Garden of Eden. For centuries they've remained hidden, but now a war is brewing to reclaim what once was theirs, and staying hidden is no longer an option. Without consent, the Lawless sirens and tritons of The Depths have struck a terrifying alliance with another former enemy, and like it or not, Cora's only choice is to navigate both politics and her pride to save two men from different worlds. One, a loyal brother-in-arms, and the other, a human soldier destined to lead…if he survives following his heart.