In the world of Ars, humans lead a decades-long war against giant beasts that ravage the lands and feed on their resources. Those tasked with fighting them are champions called nagimori, who utilize the destructive power of kannagi: beings gifted with uncontrollable magical powers. While mourning the death of his war partner, former nagimori Jiiro crosses paths with Kuumi, a young woman who has just awakened her magi...