After the sudden death of her parents, a young woman named Shiori Kanzaki finds a picture of a man that she believes to be her grandfather.

She travels to Azaka Village, where he was apparently from, in hopes of meeting him.

However, when she arrives she instead finds out that the tiny village has a museum that she realizes she lived in as a young girl. There she meets Sakuma, a middle school girl who tends to get herself in trouble, and Suga, the strange manager of the museum who only communicates in written memos.

Suga grudgingly allows her to stay at the museum for a while to research her family.

She runs across a village legend of "Kotori Obake," a demon woman who abducts children who go into the nearby forest. How is this story connected to Shiori's past? Why does she hear voices calling her, commanding her to come fulfill a promise she has no understanding of?