Sherlock went so far as to enter a relationship with her .
She is the personal assistant of Magnussen , the villain of His Last Vow , in which it is revealed that both Mary and Sherlock independently befriended her in order to get access to him .
Sherlock went so far as to enter a relationship with Mary .
She is the personal assistant of Magnussen , the villain of His Last Vow , in which it is revealed that both Mary and Sherlock independently befriended her in order to get access to him .