Every year, the Ushiromiya family attends a gathering held by the eccentric family head, Kinzou, on the island of Rokkenjima. As his health is failing, most of the family believe he doesn't have much time left. So as a typhoon rages on outside, so too does the storm in their hearts as they squabble amongst themselves over the inheritance and the claim of being Kinzou's rightful heir.

Battler, Kinzou's grandson, has returned to Rokkenjima after a six year absence, expecting the gathering to go smoothly. However, his eccentric grandfather has other plans; he enacts a bizarre game, challenging everyone to find his hidden gold. The one who finds it also receives the most coveted reward of all: the leadership of the family. However, their game is beset with violence and murder when the participants are used as "sacrifices" to revive the Millennial Witch of Rokkenjima, Beatrice.

Ever the skeptic, Battler doesn't believe in the occult. But when so many around him turn up dead, he is forced to question whether it was the work of magic or the machinations of someone among them.