The world 50 years past the tragedy.
Main character is a traveler who wanders around the Europe with a single bag. The girl he met along the way accompanies him to the Blinger Forest, where the sender of the love letter lives. She picked up the letter accidentally, but now wants to know the truth about this love letter. The Blinger Forest is full of mysteries that date back to pre-tragedy era.

[From vndbreview]