Young Qian Niu ventures into the territory of tree demons in search of the Moon Soul Herb to cure his mother's mysterious illness, where he encounters the rabbit spirit Nuan Nuan. In order to obtain the flesh of Tang Monk to save his mother, he undergoes training to become a demon. At a critical moment, his innate goodness awakens. Together with Nuan Nuan and others, he confronts the Soul Devourer King, ultimately saving his mother and the people, and protecting their homeland.