I think it could be "Where Is Moriarty?," because remember Mark said that this episode should solve the mystery of whether Moriarty is alive or not. That's just my opinion. I thought I should share.
That too!! Or it could be both? Hit two birds with one stone.
Personally I have a theory that Mary work(ed/s) for Moriarty, so it could be in finding out about Moriarty, we find out about Mary.















