Ruby leaves her beloved Arcus and travels to her mother's homeland of Sudesia, where she must pass a series of trials in order to hone her control of fire and become a Fireblood master, gaining the trust of the wary Fireblood queen and access to the knowledge that will allow her to defeat the destructive Minax.

Ruby's world has changed more than she ever could have imagined. She's in love with a powerful Frost King. She's the heir to the Fire Throne. And she may be a Nightblood--the spawn of a vengeful deity hellbent on releasing an imprisoned army of shadowy wraiths. Once freed, these beasts will roam the earth, devouring the spirits of every last person until he or she is nothing but an empty husk. Ruby is able to control the shadows to a degree, even...