This is book 4, and it would be advisable to read the exciting previous books first to get the background, backstories, and character development. There is a useful 'Cast of Characters' in the back but reading the books sequentially is best.
Ember, Herne (her lover), Yutani, and Viktor have an assignment from Cernunnos and Morganna to halt a ceremony to bring a powerful Fae warrior, Callan, back to life. They don’t succeed and Callan escapes into the world. They return to the Wild Hunt’s office to regroup with Angel and Talia. Raven BoneTalker, an Ante-Fae, comes in as a client whose fiance, Ulstair, a Dark Fae, has disappeared. Now Amber must accept the Autumn Stalkers Side of her; in a previous book she accepted the Leannan Sidhe side. There are several exciting adventures as many mysteries are solved, Ember and Herne are firmly committed to each other, Angel gets a boyfriend, Yutani finds out who his father is, and several secrets are revealed. At the end of the book, Amber is ready to face the Cruharach.