A Story Snippet, Or: When Stories Attack

I woke up with this paragraph running through my head:

It all starts with The Book: a gaudy red paperback filled with mostly-blank pages.  The first thing you do on the train ride to Fontanelle is to inscribe your name and address on its front page, so people will be able to find you.  It is said that if you are murdered in Fontanelle – a likely possibility – your killer will mail The Book back to your relatives.

Beyond that, I know nothing.  I have a vague sense of a pile of discarded, filled-out books from disappointed seekers on their way back home clogging the trashcans of the train station at Fontanelle – but I have no idea what Fontanelle looks like, nor what exactly it is that you’re supposed to write in the book (aside from a vague feeling that it comes from talking to people, but that’s the writer in me demanding scenes), nor what kind of culture prizes the quest and not the people, nor what sort of mechanism causes people to find you from writing your name in a book.
Used to be, I plotted my stories in advance, and wouldn’t start until I knew the ending.  Turns out that doesn’t work for me.  What does work is when I’m presented with a mystery and I have to work hard to find out what happens next; that tension of not knowing until you do, dear reader, fills my tales with whatever strength they have.
Now the only way I’ll know what happens is Fontanelle is to write the damn story.  I hope I do.  It sounds like an interesting place.