艾琳(星井七濑 配音)的母亲是一名兽医,两人过着相依为命的生活。一场意外的发生令母亲和艾琳即将遭受残酷的死刑折磨,在生死存亡的紧要关头,母亲用禁断的咒术久了艾琳,自己则不幸死在了猛兽的口中。 就这样,艾琳失去了自己在这世界上的唯一一个亲人,善良的养蜂老人约翰收留了无处可去的她,将她抚养成人。一次偶然中,艾琳邂逅了在天空中自由翱翔的王兽,王兽是一种高傲的物种,绝不受人类的亲近和控制,这种高洁的性格深深的吸引了艾琳,引导着艾琳走上了和母亲一样的道路。艾琳来到了位于卡扎姆的王兽保护场,开始了学习,没想到这一选择彻底改变了她的命运。In the land of Ryoza, the neighboring provinces of Shin-Ou and Tai-Kou have been at peace. Queen Shinou is the ruler of Ryoza and her greatest general, Grand Duke Taikou, defends the kingdom with his army of powerful war-lizards known as the "Touda." Although the two regions have enjoyed a long-standing alliance, mounting tensions threaten to spark a fierce civil war. Within Ake, a village in Tai-Kou tasked with raising the Grand Duke's army, lives Erin, a bright girl who spends her days watching the work of her mother Soyon, the village's head Touda doctor. But while under Soyon's care, a disastrous incident befalls the Grand Duke's strongest Touda, and the peace that Erin and her mother had been enjoying vanishes as Soyon is punished severely. In a desperate attempt to save her mother, Erin ends up falling in a river and is swept towards Shin-Ou. Unable to return home, Erin must learn to lead a new life with completely different people, all while hunting for the truth of both beasts...