Based on the visual novel of the same name.
In 1986, between October 4th and 5th, members of the Ushiromiya family gather on the secluded island of Rokkenjima to discuss the division of the family’s massive fortune upon the impending death of the family’s head, Kinzo.
However, when a typhoon traps the eighteen people present on the island, six people are mysteriously murdered. The remaining people struggle to survive as the murders continue, supposedly by the will of the legendary Golden Witch, Beatrice.