Tamahi is a high school student investigating paranormal activities and unexplained deaths within a vintage apartment building steeped in local legends of psychic phenomena. She partners with Rin, a college student, to uncover the structure's hidden secrets.

Her experiences inside the building involve direct encounters with supernatural entities and perilous, life-threatening situations. Tamahi becomes trapped within an alternate reality or Lovecraftian parallel dimension alongside others. During this confinement, she endures attacks from mysterious creatures known as "Ghost Bugs" or "Nightmare Bugs," entities linked to bodily invasion and mutilation.

A core aspect of her ordeal is a relentless time-loop sequence. Within the building's nightmarish environment, she repeatedly experiences death and resurrection. This cyclical torment embodies the narrative's thematic focus on inescapable horror and psychological trauma.