What is Mary Watson up To?

(An attempted analysis of ‘Mary Situation’ left us in ‘His Last Vow’ the 9th episode in the BBC ‘Sherlock series’.  I don’t recommend that you proceed unless you have seen seasons 1 – 3.)
The question as to what is really going on with Mary Elizabeth Watson (aka Morstan, aka A.G.R.A.), whether the revelation of “His Last Vow” has in fact left us with a true understanding of the situation, or whether there are still plots and villainies on her part yet to be revealed, has been much talked about. We could of course go over all three episodes which include her, analyse dialogue and facial expression, investigate her (and Sherlock’s, and Mycroft’s, and John’s) every move, look for apparent inconsistencies and double-meanings, and postulate all kinds of theories. And that might make sense to do. But I’m going to try something simpler at the moment.  Setting aside all these observations and postulations, I will see if I can reduce the problem to the simplest terms that I can see.  What options are possible?  I see four options we can look at. One: Mary is in fact as she has been revealed to be, there is no plot, no underhanded motives, she’s just an unscrupulous woman with a dark past who happens to have fallen madly in love with John Watson. Two: Mary is still lying, and has some kind of plot going on, but Sherlock Holmes and John Watson do not realize it. Three: Mary has such a plot, and Sherlock knows, but he has not told John. Four: Mary has a plot, and Sherlock and John both secretly know about it. And technically, to fully cover the matter, I have to list a fifth option (however ridiculous): There is a plot, and John knows about but Sherlock doesn’t. As far as I can see, any possible scenario would HAVE to fit under one of these five categories.
One – Mary is as she now appears. 
Lots of people don’t buy this. And they do have a point. Intentionally shooting Sherlock Holmes is a very understandable reason to look at everything a person says or does with suspicion. I highly suspect her of not being what most of us would be inclined to call a very ‘good person’. But that does not in the slightest make her story implausible, or provide anything resembling proof of there being ulterior motives behind her actions. While I strongly disapprove of her behavior, I can see no actual proof at this point that this is not the case.  It seems in any case, to be quite possible.
Two – Mary has a plot, but Sherlock doesn’t realize it
I suppose that is not beyond the power of the human imagination to invent a scenario where this would be possible. However, it is so immensely improbable that I should call it a practical impossibility, and I should have a very hard time ‘buying’ it if it were in fact to happen. Sherlock was betrayed and shot by someone he counted a friend, and so naturally, he applied himself to an investigation of them. That under such circumstances, he – Sherlock Holmes – could overlook a plot in action, is not believable. (And as a side note, if there is a plot, it cannot possibly center around Sherlock Holmes. She passed up what we can only imagine were countless chances to kill or otherwise injure Sherlock – so it couldn’t be a plot to kill him or make him miserable. Then, during a chance meeting which it is impossible that she could have planned, she made a spur of the moment decision to shoot him – so it could not be a plot which consisted of long term spying on him. If there is a plot, it looks as though Sherlock himself is totally irrelevant to it.)
Three – Mary has a plot and Sherlock knows but John doesn’t. 
We all know that Sherlock is perfectly willing to keep John in the dark on all sorts of matters. He does it all the time, and sometimes about very serious things. But I cannot see that happening in this particular case. Sherlock went through no small amount of effort and pain to make sure John knew about the shooting, to see that he heard it from Mary’s own lips, to show him precisely what it was that he had married. That he would have put both John and himself through such pain, and then not bothered to tell him the whole story – tell him the most important part – is preposterous. But not only did he not tell John there was a plot, he actively encouraged John to reconcile with her, just this time with open eyes and a full awareness of just who and what he had chosen to love. It is true that there have been times that Sherlock has tricked John into believing a falsehood so that John can more effectively convince the villain of it. But quite simply, I don’t think that Sherlock would do that to John here. He may have missed the fact that he was John’s best friend, but he understands perfectly well that Mary is John’s beloved. And in any case, he would not leave John in the hands of a woman who he thought couldn’t be trusted with him. Yet leave them together, he did. He was leaving at the end of the episode, and rather than warning John to get away from her before her plot became ripe, he bequeathed the care of John to her, and left them standing hand in hand. I cannot see Sherlock distrusting her intentions, and yet letting this happen.
Four – Mary has a plot, and Sherlock and John both know it. 
Plainly, I don’t think John could, I don’t think John would, do that to his wife. I could see him leaving her forever over the matter. I could see him letting that event turn his love to hatred. I cannot see him pretending to forgive her. He could not do that, and remain the man who we know. It would be an out-of-character act on a monumentally grand scale. Furthermore, even if he were to attempt it, he does not have the skill set to allow him to do so. He simply couldn’t keep up the pretense, he’s a terrible liar. (And for that matter, we’ve seen Sherlock use people shamelessly, but never extend a hand of friendship to someone when he is actually seeking to destroy them.) Also, this would seem to be directly contradicted by the content of His Last Vow. We repeatedly see Sherlock and John talking about Mary with no witnesses present, and we there is absolutely no sign of this. / When the only other conscious person in the building is Bill Wiggins – John: “Did you just drug my pregnant wife?!” _ Sherlock: “Don’t worry. Wiggins is an excellent chemist.” / When the two of them are standing alone in a field – Sherlock: “Want your wife to be safe?” _ John: “Yeah, of course, I do!” / When they are standing on Magnussen’s porch, surrounded by police, but in the presence of loud machinery, Sherlock’s: “Give my love to Mary. Tell her she’s safe now.” / And when they were saying goodbye, plots and plans were never mentioned, Sherlock just jested and asked John to name his and Mary’s daughter after him. Magnussen’s infliction of petty cruelties on John (and hence on Sherlock) was only made possible by the fact Sherlock and John were trying to protect her. If they were counter-plotting against her, this would just not happen.
Five – Mary has a plot, and John realizes it, but Sherlock doesn’t. I think we can all agree that this doesn’t even need discussed.
Conclusion. Option one is open to suspicion.  But options two, three, four, (and five) seem to be practical impossibilties.  I do make the disclaimer that the BBC can technically do whatever they like with their series, in whatever defiance of logic, consistency, and character that they like. … But so far, they’ve proved themselves far too competent to do so.
When you have excluded the impossible, whatever remains must be the truth.
And if I may go meta for a minute, the name of the episode is His Last Vow. Sherlock’s vow was to be there ‘for all three of them … whatever happens’. What is that episode, but precisely that? … The very name of the story seems to preclude all the plotting and counter-plotting I’ve seen suggested.
Therefore, primarily by the process of elimination, I conclude that Mary Watson does not have a evil plot going on.
What do you think is going on with Mary?  Tell us below in the comments!
Sherlock criticism by Charlotte Ann Kent