In the sequel to Treachery Queen, the Seelie Court has declared its war on the world, and nothing will ever be the same.

It has only been a week since Pasiphae of Eo entered a fake marriage alliance with the Seelie Crown Prince in a bid to forestall his mother's coming invasion on Medeis, Pasiphae's homeland. Now, those who were once enemies have disappeared into the shadows, while new contenders have clawed their way into power. Amidst the chaos, there is only one possible outcome that ends well for Medeis: Seth must have the Seelie throne, and Pasiphae takes it upon herself to ensure it.

Meanwhile, Circe of Eo has turned diplomat. The Unseelie Queen knows that invasion is coming, and is desperate to snatch the Isles, where the humans make their home. To keep it from her grasp, the witches must conquer the land first, for the humans' own good. But the Isles has secrets of its own, and if Circe isn't careful, she may be swallowed by the rising tide.

From a perilous journey into a country that kills all who enter, to a mission into the Seelie Court during its midnight sun, the two sisters will do anything to protect Medeis. Heads will roll, hearts will be broken, and if the world is to fall a second time, then so be it.