Last night, in having a conversation with @softbunny52, I came to an epiphany.
So in the first two series, the only music we get that has lyrics is all tied with Moriarty, such as “Staying Alive” and “Sinnerman.” That’s really it for lyrics in the entire first two series. With so little lyrical music, it becomes easy to draw the connections between them, which in this case is obviously Moriarty. All of these moments have something to do with him and thus lyrical music becomes a good shorthand for Moriarty.
But in series three, we get more bits of music with lyrics, the main ones being “Donde Esta Yolanda” and “December 1963.” (softbunny52 mentioned that there was also Rihanna’s “We Found Love,” but I don’t remember where or the context for that. I really wish I could because that might add to or disprove this meta. But anyways…) None of these moments involve Moriarty, so what could that mean?
Now, I’ve seen a lot of various meta floating around on “Donde Esta Yolanda” and “December 1963″ having some subtextual links to Johnlock. (Really wish I had links to those metas, but I can’t remember them and, sadly, never actually save these things. If anybody knows, please link me!) But, if we hold to the theory of the previous two series, music with lyrics is tied very closely to Moriarty. So in what ways can these moments be tied to him?
I think the answer lies in who all is involved in and heavily tied to these moments: John, Sherlock, …and Mary.
Mary is this new edition into the dynamic of these two characters. Moments with John and Sherlock never had music with lyrics playing in the background before. It’s not until Mary is introduced that we see this new trend. So it stands to reason that that she is the thing that is making these lyrics appear.
Therefore, according to the theory above, she must be in some way tied to Moriarty as well.
To me, I think that this points to Mary working for Moriarty. Definitively.
Which could also mean that these moments between John and Sherlock are orchestrated by Mary and, by extension, Moriarty. I don’t know what this means for the validity of these Johnlock moments yet, but it would be interesting to figure that one out.