Lady Elizabeth Smallwood

As always....***SPOILER ALERT*** 

I don't trust Lady Elizabeth Smallwood any farther than I can throw her. "I haven't done any of the things you're accusing me of," she tells Mycroft when he interrogates her in "The Six Thatchers." I did not like her word choice when I watched it the first time, chalking it up to shoddy writing, but then she flirts with him in "The Lying Detective."

Here is my theory. Lady Smallwood has been a double agent for years, but when she is finally confronted, Mycroft accuses her of a betrayal she did not commit. She is then able to say with complete honesty that she is innocent. However, she now knows that Mycroft is not above suspecting her of committing treason, and she, therefore, needs to keep Mycroft on her good side. What better way for her to do that than by using her feminine wiles? Smallwood will not succeed in seducing Mycroft, but it will succeed in distracting him. This will, no doubt, confuse Mycroft, and he will focus on her flirtatious behavior rather than her work with either Moriarty or Euros.

Interference from the Woman

As always ***SPOILER ALERT***

The Woman first comes to the attention of Sherlock in the episode "Scandal in Bulgravia." Or does she?

In "The Great Game," Sherlock receives a letter which he notes was written on Bohemian paper. The fact Sherlock initially says Bohemia and not Czech Republic could be more than just an nod to "A Scandal in Bohemia." I believe it is a clue pointing us in the direction of The Woman. After all, Sherlock also points out that the letter was obviously addressed by a woman.

The Bohemian paper could just be a playful red herring by Gatiss and Moffat, and some other woman could have addressed the letter under the direction of Moriarty. However, there are other allusions to "A Scandal in Bohemia" in this episode. Sherlock is able to guess Molly's weight gain (just as he does with John in "His Final Vow"), and the line "I'd be lost without my blogger" is an updated version of the line "I am lost without my Boswell" in the aforementioned short story. Lastly, the first time Sherlock receives a call from the bomber, the villain makes the person doing the talking call Sherlock "sexy." In the very next episode, The Woman states that "Brainy is the new sexy."

Could it be that The Woman becomes involved in The Game much earlier than we have been led to believe?