Katakuri Kona

The main character, Yuka Inose, has moved to a high-rise tower apartment with her family. As soon as she moved in, she was taken away from the apartment mount by the residents who said "upper floor is better". Yuka tries to get used to her life even though she feels uncomfortable. However, one day, she takes on a board member from her neighbor, and she becomes involved in the Darkness of this apartment...