Once upon a time there lived a grandfather, a grandmother, and a dog. They picked up a puppy that had been abandoned and maimed, and raised it, loving it as if it were their own child. Eventually, the puppy grew up and its fur became white and beautiful. The old, greedy, and violent couple living next door thought, "If we kill it and strip it of its fur, we can surely sell it for a lot of money. When the old man and woman, who were looking for their child who had suddenly disappeared, found him, the dog was already dead. Many years have passed since then, and the grandmother has disappeared, and a baby with beautiful, translucent white skin appears before the grandfather, who lives alone with the child born from a peach. The baby, who had landed from the sky surrounded by light, had dog ears, a birthmark on his left arm, and a prayer bead on his right wrist with the word "filial piety" on it. Soon, the dog-eared boy, who had the appearance of a woman that everyone would admire, set out on a journey together with a boy born from a peach. On a journey to exterminate demons. あるところにおじいさんとおばあさんと一匹の犬が住んでいました。捨てられ、傷つけられていた子犬を拾って育てた二人は、我が子のように可愛がっていました。やがて成長し、その毛並みは白く美しいものになりました。「殺して毛皮を剥ぎ取れば、高く売れるに違いない」そう考えたのは、隣に住むいじわるで欲張りで乱暴な老夫婦でした。突然姿を消した我が子を探していたおじいさんとおばあさんが見つけた時には、もう犬は亡くなっていました。それから、幾年月が過ぎ──おばあさんも消え、桃から生まれた子どもと二人で暮らすおじいさんの前に現れたのは、透き通るような白く美しい肌を持つ赤ん坊でした。光に包まれて空から舞い降りたその赤子は犬耳を生やし、左腕にアザがあり、右手首に“孝”の文字が入った数珠をつけていました。やがて、誰もが見惚れるような女性の姿をした犬耳の少年は、桃から生まれた少年と共に旅に出ます。鬼退治の旅へ。