Wall Road Journal bestselling author Jeff Wheeler continues his wondrous Harbinger series in which two young women unite mainly because two worlds approach the brink of war…

Though relations between Princess Seraphin Fitzempress and her father have already been strained, Sera’s royal position has remained unchallenged. Filled with self-doubt, she struggles to understand the Mysteries—her very best trial yet.

An education in the enigmatic magic is certainly a necessary 1, should Sera intend to rise in her station and invoke her about Mirror Gate powers during battle. However the emperor’s death today leaves both Sera and her ambitious dad eligible for the throne—a competition the prince regent intends to win. Even if it means an alliance using a rival empire.

Sera’s hope lies in Cettie, a waif raised in the world below, whose life offers intertwined with Sera’s in one of the most unexpected methods. The Mysteries arrive quickly to Cettie, and her studies have started to yield fresh insight into her growing power. But those same forces place Cettie in the path of those who destroy her.

Now as the risk of war ignites and an insidious sickness spreads through the entire kingdom, Sera and Cettie should collect their courage and fight for each other’s lives…and for future years of their endangered world.