Sherlock Series 4: 8 Huge Predictions (And Why They Need To Happen)

8. Mary Watson Is Going To Die (And So Will Her Baby)

Mary might now be married to John Watson, but there's a lot about her that we don't know. Her CIA past makes her something of an enigma, and though she appears to care a lot about John, it's not impossible that she has some other motivation (or initially did, anyway).

Still, Mary has been something of an anchor for John's character, and has been an important aspect of his development. Yet according to writer Steven Moffat, Series Four is going to enter much darker territory than ever before. What this is likely to amount to, then, is the death of Mary and her child. Having a newborn hanging around would only make plotting the show infinitely more difficult, and revealing her pregnancy is likely to have been a tactic to up the dramatic stakes when she's eventually endangered.

As for why it needs to happen, the show has really lacked a central "villain" for some time now. Ever since Moriarty's death, Sherlock and Watson have gone up against brief antagonistic forces, for example Charles Magnussen, but the overall narrative has definitely suffered from a lack of overarching threat. With the confirmation that Moriarty is definitely dead, it's the perfect time to bring in a new villain to carry us through the fourth series (having him manipulate the image of Moriarty to attack Sherlock would be particularly interesting).

By killing Mary and her child off, this would immediately establish how dangerous this new threat is, and it would also propel Watson's character into a much more complex narrative place. As the more "human" of the detective duo, giving Watson a darker story line would be a valuable way of fleshing out the narrative without risking spoiling the enigma that is Sherlock.