Sherlock: 10 "Mouthwatering Ideas" For Upcoming One-Off Special

1. The Valley Of Fear

So far, three of Doyle's four Holmes novels have been at least partially adapted for the series: A Study in Scarlet became A Study in Pink, The Hound of the Baskervilles became The Hounds of Baskerville, and The Sign of Four became The Sign of Three. That only leaves The Valley of Fear, and considering the pattern, you'd think it would be best to leave that until Series 4. In fact, doing it as a one-off might be the best way to go.

Some of The Valley of Fear has been tackled before: its most famous line ("Dear me, Mr. Holmes, dear me!") became Moriarty's text to Mycroft in A Scandal in Belgravia. But it does mark the first appearance (chronologically) of Moriarty, giving the writers a means to answer the cliffhanger at the end of Series 3. If Moriarty is truly dead, it can be dealt with in a self-contained manner and we'll see no more of Jim, except in Sherlock's mind palace. If he isn't, and is casting the same manipulative shadow that he does in the novel, it would be the perfect set-up for a dark and gripping Series 4.