The triangulation
While Morland brought Watson into Sherlock's life several years ago, he didn't foresee a partnership forming. She may not have known what to make of him, either.
"Joan and Morland never met, they never talked face-to-face. I believe they were limited to email exchanges," Doherty explained. "She doesn't really have a sense of the man. She's certainly heard Sherlock complain about him for three yeas, she knows what Sherlock's take is, but she knows Sherlock is prone to exaggeration when he's complaining about family or would-be friends. She's ready to meet dad and form her own opinion of the man. And yet, even she has to admit Morland's timing doesn't seem to be great. He's arriving at a very difficult time. Even though he may want to help Sherlock, that may not be possible. She's open minded about everything, but what we will see as we begin the season is some trepidation on her part, some suspicion. I think she's going to begin to consider the possibility that if dad isn't exactly what Sherlock's been saying he is, he could at least be close to that."
"Joan is like a guard dog for Sherlock," Noble added. "She thinks that this man is responsible for his demise"
Doherty said that fans may have an opportunity to learn more about Watson's family this season, and even be introduced to her step-father—and their own complicated relationship.