The Client's Dead
The year is 1912. You are a famed (or perhaps, once-famed) detective. A solver of puzzles. A person to go to when murder most foul happens, especially those mysterious cases that has the police stumped.
So it is not unexpected that you receive a letter in the mail seeking your help. It begins...
I have heard of your fame in solving murders, and would like to hire you to solve one. My own, as it happens. For by the time you receive this, I will be dead..."
It may be personal pride, to take this commission. It may be greed. It may be desire for fame or recognition. Whatever the case, you travel with letter in hand to a remote part of Europe, and then the game begins.