mizuki has been living with her father since her mother died. Recently, because of her father's work, she moved near her grandfather's house, and they had more opportunities to eat dinner together as a family. One day, her father said he couldn't come home from work, so mizuki ended up staying at her grandfather's house. Then, her grandfather said, "Since you're here, why don't you see my work?" and invited her to the storehouse. To mizuki, who innocently entered the storehouse, her grandfather brought out ropes…