On the verge of marriage, Haruko (Yuu Kawakami) visits her grandmother's ancestral home for the first time in twenty years, accompanied by her brother, Junichi. Deep within the house, they discover an old traditional prison room. When Haruko asks her grandmother about its origin, she learns that her great-grandmother was once imprisoned there. That night, Junichi has a strange dream—of a woman bearing the same name as his great-grandmother, being repeatedly violated by men and having her pure body destroyed. The grandmother's words and the vision of the dream intertwine, leaving both siblings deeply shaken.