Asked about Sherlock's mother, Doherty said there's been some discussion. "I feel like we have an obligation at some point this season to flush out that story and explain why she isn't featured on the show alongside Mr. Holmes. It's a story we need to tell. We need to find the right moment. I think mom is a big reason why Sherlock and his father have struggled to the degree that they have, or struggled as father and son."