Yamijima is a place that has felt the influence of a supernatural being called Annaki (and the things created from its bones), and as such has been feared since ancient times as "the island of darkness", "island of the underworld" and "the taboo island". This is due to the fact that Mt. Shinari in the centre of the island and the Mekkoju, which exists in the World of Nothingness, were once overlapped in their dimensions, leading the islanders to develop unique traditions and legends involving "impurity", and several strange incidents such as the mass disappearances and undersea cable cutting of 29 years ago occur on Yamijima because of the special location in which it is positioned.
The people are all swept into the Yamijima in the Reflected World created by Mother by a huge, red tsunami that occurs along with a siren at midnight. Escaping from this illusionary island becomes the story's ultimate objective.
- 1890 - Yamijima Fort construction completed
- 1960 - Investigation team enters Yamijima
- 1961 - Mining begins on Yamijima; pylon constructed
- 1963 - Apartment complex constructed
- 1965 - Amusement park constructed
- 1967 - Development reaches peak. Record population on Yamijima
- 1970 - Ore gradually dries up; other issues besides...?
- 1973 - Yamijima gold mine closes
- 1975 - Ryuhei Mikami moves to the island with Shu
- 1976 - Undersea cable cut; Yamijima islanders vanish; (Hanuda Village landslide)
- 1986 - Ferry runs aground
- 2003 - (Hanuda Village landslide)
- 2005 - Yamijima turns into Other World