Time just passes.
I came to this story because I am a fan of Oshimi and I decided to read all her works, Kusakabe is a girl with a disorder, it would be very interesting know what led her to have that behavior while the man does'nt think about her past or Her future. Maybe he loves her in a genuine way or maybe he just fills that inner loneliness that is reflected in his eyes.
People are consumed by our demons, each one has an addiction or a punishment in their own way. We only feel "happy" in our area, for Kusakabe his area was that man.
It is a short but shocking story, if you have a few free minutes of your day give it a try.