Three in the Mirror

I woke up one night to a faint rustling sound. I lay there, listening, and the sound soon stopped on its own. I decided to go to the bathroom and got up. I went out into the hallway (from there, the kitchen table is visible through the mirror). The light in the hallway is always on at night, and through the mirror, I saw people sitting at the table—an old woman, an old man, and a child with them... I froze, and then the old woman started to get up. I ran out onto the landing and started ringing the neighbors' doorbells. When we came back together, there was no one in the mirror or in the kitchen.

Only later did they tell me that an elderly couple with their grandson had lived in this apartment before me. When both adults died, the child was taken to an orphanage. What happened to him afterward, no one knows. That's the short story.