Название книги: Unseen

After Cassiel and Warden Luis Rocha rescue an adept child from a maniacal Djinn, they realize two things: the girl is already manifesting an incredible amount of power, and her kidnapping was not an isolated incident.

This Djinn—aided by her devoted followers—is capturing children all over the world, and indoctrinating them so she can use their strength for herself. With no other options, Cassiel infiltrates the Djinn's organization—because if Cassiel cannot stop the Djinn's apocalyptic designs, all of humanity may be destroyed.