One day, a mysterious letter 'F' starts to be written on doorplates in a condominium building. Since then, mysterious incidents consistently occur around Yukari Yamamoto, who is an ordinary female high school student living in the building.
6/6/2015
4/15/1988
4/17/1987
9/29/1974
8/7/1942
4/3/1981
2/5/1988
5/10/2019
7/11/2023
1/1/2001
5/30/2015
5/22/2024
3/24/1939
10/1/1958
7/29/1988
9/1/2020
2/6/1946
3/6/2023
1/29/2024
1/15/1999
11/29/1964