Sherlock.

If you haven't checked out the tv show of 'Sherlock'. Do it.  Not only is it one of the best written shows around at the moment, but its full of excellent acting, excellent story lines and best of all good old fashioned mysteries.  Stepehen Moffat (Dr Who, Coupling, Tin Tin) writes extraordinary 1.5 hour episodes,which make you so engrossed in whats happening you forget you've essentially just watched a movie. If you want to study story structure - watch this show!  Benedict Cumberbatch and Martin Freeman make an excellent Holmes and Watson (respectively), impeccable acting.  The last episode, Martin Freeman was simply sublime. Your heart was with him the whole time, and Sherlock's 'note' was heartbreaking.
So - dare I ask the question?  For those who have seen it, what do you think happened?  Moffat has said 'there is a clue everyone has missed'.  I have a few theories, and there are plenty circulating the internet, but for those familiar with the show, and with Moffats (and Gatiss's history although he didn't write this episode) previous record all the theories I've read so far, are to plausible.  Too obvious, too un-Sherlock!  My theory? Well, i might divulge if people comment, if not, I don't want to spoil the fun xx