在平安时代，妖魔还栖息在森林，山野和河流中。一个变装成男人的女孩，被她所爱慕的人陪伴着，与妖魔战斗。这个勇敢的女孩，又叫“怪童丸”，上臂有一个汉字“焰”的纹身。她是誓死保卫京都安宁的四大护法之一。怪童丸为了荣誉和为保卫京都献身的爱人而战斗。而从小和她玩到大的“鬼公主”，现在竟成了她最大的敌人……
This story takes place during the Heian Period of Japan`s history, when evil spirits still resided in the forests, mountains and rivers. A girl, accompanied by her loved one, battles against these evil spirits, while she is disguised as man. This brave woman, aka "Kaidomaru", with a Chinese character "Flame" tatooed on her upper arm, was one of the "Four Devas". Kaidomaru fights for the honor of her lost love, Raikou Minamotono, who had sacrified his life in order to protect the capital Kyoto, from the evils deeds of a "princess" cursed by a malicious ogre. The princess, whom Kaidomaru used to play with as a child, has now become her ultimate enemy.
(Source: Production I.G.)
