Yoji Minamimaru, known by his nickname Nanmaru, is a university student with a supernatural ability to create small holes in anything. One day, Yoji finds out that the professor of folklore studies has gone missing after conducting fieldwork in Marukami Village. At the same time, a mysterious murder occurs in that very same village. Together with his classmates, Minamimaru decides to head to Marukami Village to look for the professor, stumbling upon an eerie, out-of-season Tanabata Festival. Before long, the group finds themselves embroiled in a web of paranormal mystery.