大学生の梶浦太郎は観音姫様という伝説を調べるため、気になる美人の先輩・夜戸ハルを含めた研究グループで、遠く離れた孤島・伊喜島を訪れる。しかし、夜戸ハルの出身でもあるこの島には、祭りの間によそ者が居てはいけないという古くからの決まりがあり……。豹変した島の住人たちが梶浦に迫る……！
Taro Kajiura and his friends from a research group at Tonan University embarked on a trip to Ikishima Island in order to pursue the origins about Princess Kannon. At the same time, the villagers of Ikishima were holding an annual festival in which outsiders were forbidden to participate in for over 400 years. The consequences for breaking that tradition were much more severe that any of them had imagined…
