As I was about to step out into the garden, my gaze was caught by the pictures in the hallway that had already caught my eye yesterday. Many of them seemed ancient, but one in particular caught my attention: it was the last one in the hallway.

It showed a family of four—a mother, a father, a girl, and a boy. They all appeared unusually pale, but their faces were adorned with friendly smiles. They were standing right in front of this house, but their clothes looked as if the photo had been taken many, many years ago.

I looked at it more closely because something about the boy seemed...