Sentan Island rests quietly in the Yuden Sea, a small landmass untouched by the ongoing conflict between the Northern Government and the Southern Continent Free Zone. There, Akiyuki Takehara lives a peaceful existence with his mother, Fusa. Though his father, town physician Ryuzo, no longer resides with them, the connection between father and son remains strong. One day, after delivering the lunch Fusa prepared to his father as he always does, Akiyuki heads to school. There, an explosion erupts around him and his companions Haru and Furuichi. From the blast emerges a strange radiance that seeps into Akiyuki's arm, bringing unbearable agony. Before he can make sense of what's happening, the white-haired girl he encountered on the bus appears, leading him toward a power beyond anything he has ever experienced.