The letter was thin enough to just slip between the metal slot and the plaster wall that housed it. It was there, stuck between them, for a few dozen years, until there were renovations, and it, along with a few others, were found. The postal service tried to deliver all of them, but the letter was the only one that couldn't, and that had no return address.
The discussion was animated, until it was decided to open it, and hopefully find clues.
I was chosen.
First to open it, then by the letter inside, which had my name written down...