Tess O'Connor is the not-quite-mortal Bearer of the Iron Sword. After her encounter with the Exiled and the bone sorcerer, she's on edge and eager to return to the mortal world to fulfill her oath to the Queens to kill the bone sorcerer. Dragon-slayer Calliea has nearly everything she's ever dreamed of: command of the Valkyries, a place in the High Queen's Wild Court, a handsome man who loves her...and then her world is turned upside down by her rescue of an Unseelie woman from Mab's hunting hounds. Mortal Vivian has always loved tales of other worlds, and her encounter with the Sidhe has opened her eyes to the possibilities of her own potential, but she quickly learns that danger goes hand-in-hand with her decision to ally herself with the Fae. And Vell, the High Queen, watches Queen Mab's spiral into darkness as the possibility of restoring the heir to the Unseelie throne draws closer to reality. Vell must choose between allying herself and her young Court with Queen Titania to confront Mab, or protect themselves and let the Unseelie choose their own path. Follow Tess, Calliea, Vivian and Vell in this richly imagined adventure as the fate of the Unseelie Court once again hangs in the balance...