So The Lie in Leinster Gardens came around on my playlist and it’s very sad and inspiring piece; what if Mary has some tragic backstory (well for sure there is something tragic one way or another), something sort of Vesper Lynd (Casino Royal) going on. She’s assassin because of some reason. What if she was blackmailed and is blackmailed to get close to John because she’s protecting someone else? It doesn’t have to mean she doesn’t love John, on the contrary. And well I would wager it’s not other boyfriend/husband but rather member of her family: either like in The Sign of Four (with Agra treasure and stuff;)) it’s her father or maybe brother/sister/mother or even whole family.
edit: this sounded ground-breaking in my mind while it’s what is rather common idea of what may be going on after second thought.
But there might be still someone who she’s protecting…
Another interesting theory about what we might find out regarding Mary. Could it be related to what Sherlock initially deduced about her?
honorary-fangirl asked: What if Moriarty kidnaps John and Mary's daughter, and all of s4 is about getting her back, because that's what Sherlock does for his best friend and also something really cute is gonna happen with Sherlock and John like some cute bonding moment or like a really soft kiss to the cheek or something idk I just want one of my ships to be canon for once.
Baby Watson in peril already! That kid is going to have a hell of an exciting life. Thanks for sending in your theories.