Kimi no Katachi ga Utsuru

The protagonist is a ghost member of the science club. One day, his senior calls him to investigate a mysterious scientific phenomenon at school. He goes with two friends to the night school and witnesses some male and female students having sex there. The next morning, it turns out that a mirror phenomenon occurred during the night. Various rumors swirl about doppelgangers, death, happiness, and other dimensions linked to the mirrors. The investigation is just beginning.