Lost in the Fog
You follow the little footprints deeper into the woods. The trees grow tall and dark around you. Then, slowly, a thick gray fog rolls in. It covers the path. It covers the footprints. It covers everything.
You call out, "Hello? Is anyone there?" But only the wind answers back.
For hours and hours, you wander between the misty trees. The letter is still in your pocket. The secret code is still a secret. Who sent it? You may never know.
At last, you find your way home, tired and alone. Some puzzles, you think sadly, are never solved. The End.