The Ghost Letter

Your character receives a letter from someone who died years ago.

This mysterious circumstance can be the initiation of an extensive trail into uncharted territories of the past. What does the letter say, and who sent it? Why was it only delivered now, and what course of action will your character take upon this revelation? This prompt allows exploration of the coexistence of the past in the present, stimulating suspense through the concept of time, loss, and the supernatural.