Tenjite Koi to Iki

A high school teacher named Yoshitake discovers a piece of paper from the 1960s in an old part of the school. The paper lists the name Yosuke Haruoki as the author of a short story and Mikumo Sakagami as the story's main character. Yoshitake and his coworker, Yahiro, experience a series of unusual events that lead them to suspect that Haruoki and Sakagami might have been their past selves.