Since the existence of human beings, "filth" has been constantly appearing to disturb the stability and tranquility of the world. In order to fight against filth, a group of people called "Onmyoji" bravely stood up and joined the battle, using their wisdom and courage to protect mankind. The young boy Yan Motang Lulu (voiced by Hanae Natsuki) is determined to become the strongest Onmyoji in history, but because of a tragedy, he realized that the disaster was irreversible, so he gave up his ideal and became a passerby. One day, a Kyoto girl named Kanono Hongxu (voiced by Pan Huimei) appeared next to Lulu, and the two began to live together by accident. Hongxu's determination to eradicate filth gradually influenced Lulu, allowing him to see hope again and ignite his blood. At the same time, Lulu discovered that Hongxu's brother Ishigami Yuto (voiced by Murase Ayumu) was inextricably linked to the disaster that made him lose everything that year.