The link between the human world and the youkai world has weakened in recent times. The demon-vanquishing Isami visited the Takemori shrine deep in the mountains, carrying a talking rock, who is actually a youkai Masaru who had been sealed inside. The miko sisters Mamori and Inori told them about recent events that they thought were caused by the youkai. They were sent to investigate, but instead found Himawari, the youngest of the three oni siblings who lived in the nearby castle stronghold. She accused Masaru of being a traitor and killing his own father, who was the past leader, three years ago. Isami reluctantly released the seal on him so that they can repel the youkai forces. After doing so, they continue to proceed towards the castle stronghold in order to bring peace to the area, and also for Masaru to clear his name.