Returning to their childhood home on the island of Shikoku, old friends Hinako and Fumiya learn that after they departed their 16-year-old friend Sayori drowned. Sayori's mother is convinced that her daughter is trapped in the spiritual world, and Shikoku is the gateway to this other realm. Hinako begins to investigate her friend's death and is visited more than once by Sayori's spirit. The closer Hinako and Fumiya get to the truth of Sayori's disappearance, the more they realize how frightening the truth may be.