The Last Visitor

I work part-time at the library, and every night before closing, I have to check if anyone is left in the reading room. One night, I found an old, open photo album on the seat at the very back. It was filled with pictures of the library, from when the new building was completed to events over the years. When I turned to the last page, I froze. The photo showed the current reading room, but the date was twenty years ago. In the picture, a man was sitting in the back seat, looking down at a book. That face was exactly like mine. I immediately took it to the director and asked. After a glance, the director's expression suddenly darkened. "Wasn't this album sealed away long ago?" I pressed him about who the person in the photo was, but he only said, "After closing tonight, don't go into the reading room again." At 10 PM, I turned off all the lights and was about to leave when I heard the sound of pages turning behind me. I turned around and saw someone sitting in that seat. He looked up, revealing a face identical to mine. "You've finally arrived." I stood frozen. He pointed to the album on the table, and a new photo had been added to the last page at some point. In the photo, I was standing at the entrance of the reading room. And he was sitting behind me, smiling. The next day, the director was briefing the new part-timer on closing duties. "Remember to check the reading room. If you find an old photo album, whatever you do, don't turn to the last page."