The Manuscript
They found their grandfather's manuscript buried in a box in the corner of the attic. It was almost thrown out with yearbooks and tax documents that not even an archeologist would find interesting. But Rebecca saw Papa's name typed on the cover page, and fortunately set it aside for later examination.
There was debate over what they would find inside. The consensus was it would most likely relate to Papa's service in World War II, though the sisters were pulling for a good old-fashioned love story about their grandmother.
No one was expecting a Romantasy novel featuring centaurs and fairies.
For the prompts Manuscript and Letter.