Set after the events of Yami no Koe 3, Ibunroku returns to Sayoko's mansion as she summons a storm to ensure two new visitors wash up on her island: Kagami and her younger brother Mamoru.As Kagami encounters and is influenced by the mansion's various residents while waiting for the ship to come, Sayoko discovers something strange about her.

Set after the events of Yami no Koe 3, Ibunroku returns to Sayoko's mansion as she summons a storm to ensure two new visitors wash up on her island: Kagami and her younger brother Mamoru.As Kagami encounters and is influenced by the mansion's various residents while waiting for the ship to come, Sayoko discovers something strange about her.