"Inyouchuu Etsu" follows the story of sisters Mikoto and Takeru, who, along with Yamato, visit a mountain village as the final stage of their demon exorcist training. During their training, it is discovered that Yamato's body is gradually transforming into a monster due to a demon sealed within him. To save him, Mikoto and Takeru must use the ultimate spiritual power of the Haramiko, sacrificing everything to stop the demonic transformation and uncover the secret behind Yamato's condition.