As customary per year, the entire family is gathering on the island for a conference that discusses the current financial situations of each respective person. Because of the family head's poor health, this year involves the topic of the head of the family's inheritance and how it will be distributed.
However, the family is unaware that the distribution of his wealth is the least of Ushiromiya Kinzo's concerns for this year's family conference. After being told that his end was approaching by his longtime friend and physician, Kinzo is desperate to meet his life's true love one last time: the Golden Witch, Beatrice. Having immersed himself in black magic for many of the later years in his life, Kinzo instigates a ceremony to revive his beloved upon his family's arrival on Rokkenjima. Soon after, a violent typhoon traps the family on the island and a string of mysterious murders commence, forcing the eighteen people on the island to fight for their lives in a deadly struggle between fantasy and reality.