Eimi, a female college student, decides to work as a nursing care volunteer at an elderly couple's home. - But there was a room in this house where the door should never be opened... There were signs of people other than the elderly couple, and by the time they noticed something unusual about this house, it was already too late. - Eimi is attacked by someone and dragged into the room in question. - Eimi's abnormal confinement life begins as she gradually becomes aware of the darkness of the modern age, ``Kodooji.''