The Caged Queen (Iskari, Band 2)

Once there were two sisters born with a bond so strong that when they were angry, mirrors shattered, and when they were happy, flowers bloomed. Roa and Essie called this magic the hum, and it forged them together?until a terrible accident took Essie's life and trapped her decaying soul in this world.

Dax?the heir to Firgaard's throne?was responsible for the accident. Roa swore to hate him forever. But eight years later he came begging for her help, determined to dethrone his father, under whose oppressive reign Roa's people suffered. Roa made Dax a deal: She'd give him the army he needed if he made her queen. Because only as queen could she save her people from Firgaard's rule. Together, they won the war. But now Dax is proving to be an untrustworthy king, and Roa is struggling to stay ahead in Firgaard's treacherous political class.

When an opportunity arises to vanquish this enemy king and rescue her beloved sister, Roa must seize it. During the Reliquishing, when the spirits of the dead are said to return, she will have one chance to reclaim her sister for good.

All she has to do is kill the king.