There was just one rule: don’t open the door. This would soon become crystal clear to two kids making their way to this very house.

It was winter, and the snow was piling up in the quiet Maine town of Ankara. It was a strange little place, with hardly any families that had kids. Most had grown up and left for college, while others just weren’t around anymore.

Mrs. Johnson said, “I think David and Kieran will really...