The story is set in Japan's Heian Period, a time when evil spirits still dwelled in the forests, mountains, and rivers. A girl, accompanied by her beloved, battles these malevolent entities while disguised as a man. This courageous woman, known as "Kaidomaru," bears a Chinese character for "Flame" tattooed on her upper arm and was one of the "Four Devas." Kaidomaru fights to avenge the honor of her lost love, Raikou Minamotono, who sacrificed his life to protect the capital, Kyoto, from the evil deeds of a "princess" cursed by a malicious ogre. The princess, with whom Kaidomaru played as a child, has now become her ultimate enemy.