The story begins in the past as Roselyn, a young noble girl, wakes disoriented in a dark field, calling out for her retainer, Joachim. The chapter ends with her continuing to wander lost in the forest.

Chapter One jumps to present time where Roselyn, now known as Mirari, lives in the village of Solarin with her adoptive brother Salathiel. He scolds her for her reckless behavior in town. Their discussion leads to their other brother, Gaven, now a leader in the rival empire of Althaea. Salathiel leaves for work, but does not return. Mirari searches for him through Solarin, but finds no answers.

The story switches to Gaven's perspective, as he debates with Councilor Suzan about repealing the Separation Law in Althaea. Gaven had recently become the new region leader, but the majority of his people do not agree with the decisions he makes. Riots and unrest grow, forcing Gaven to authorize violence against rebels. Meanwhile, Mirari is visited by Joachim, and they begin searching for Salathiel.

The night before the raid on Rhea, Gaven is attacked by an unknown man. The man uses a dark mist that makes Gaven hallucinate and fill his thoughts with regrets. His change goes unnoticed, and during the attack on Rhea, he betrays his own army, siding with the rebels.

News of Gaven’s betrayal reaches Mirari and Joachim. They join a coalition preparing to stop Gaven, led by a mysterious masked man known as Fangbane. For the first time in history, the three empires of Althaea, Minetta, and Valenia join forces. During their strategy meetings, Mirari offers insight into Gaven’s next move. While she does her best to save Gaven's life, many want him dead for his betrayal.

Gaven’s forces move through Fox River. While Gaven infiltrates Fangbane's camp, Fangbane sends a small force to ambush Gaven's rebels. He duels with Region Leader Ahden, and Mirari attempts to reach him through words. However, she fails, and Ahden dies protecting her. Fangbane also loses precious fighters during his ambush on Gaven's camp. The heavy loss makes Mirari reconsider whether she is truly capable of saving Gaven's life. She reflects on past guilt and Gaven’s transformation, but ultimately remains committed to saving him.

Gaven’s rebels are ambushed in Ganmali. During the battle, Mirari joins the fight with Joachim. Joachim is fatally wounded, and in frustration, Mirari's fire powers awaken. She subdues Gaven and purges the darkness from him. Both are left weakened and with no memory of what happened.