Kono Shima ni wa Midara de Jaaku na Mono ga Sumu

Synopsis

Tarou Kajiura and his friends from the same folkloristic research group at Tonan University went on a trip to Ikishima island in order to pursue the origins of the myth about princess Kwannon. At the same time the villagers of Ikishima were holding the annual festival in which outsiders were forbidden to participate in since 400 years. The consequences for breaking that rule were more severe that anyone had imagined... (Source: MU)

Anime adaptations