I have most of the series but haven't read past the second adventure yet, and I'm seeking some spoiler-free clarification on something. The text blurbs on the last three adventures in the series speak of three possible endings. Does that mean that you run your players through the first nine, and they then choose one of the remaining three adventures to complete (so that it will really be experienced by any given group as a ten-part series), or merely that you can end the series after 10 or 11 parts instead of all 12 if you wish?