I really enjoyed this episode, for the suspense of what trap would be laid by the Holmes sister Eurus next, the bizarre fate of the little girl on the plane, and the mystery of Redbeard.
The Little Girl On The Plane
I don't quite understand how Eurus pulled this part off, how she was producing the voice of the scared child. Pre-recorded? On the fly? I was certainly worried about her until the point were she remained in the air on that plane for hours and it never went any lower or arrived at the city in the distance.
The Trap Rooms and Forced Moral Choices
Having someone have to choose between who might be killed, or asking them to kill one of two who are held dear, it's always an impossible situation with no good outcome.
Somehow the Holmes boys and Watson managed, with one "win" and one "loss". I found Mycroft to be particularly interesting in these scenarios. Such a fussy, fussy man. Sherlock was brilliant but humane, a long in the making story arc for his character.
So much of the characters of Mycroft, Sherlock and Eurus was revealed in the childhood scenes were there was little dialog, but the children were so much what they would become. The little girl playing Eurus was so cute, but she had sociopath writ large on her tiny features.
Heartbreaking enough to hear the story of Redbeard, Sherlock's missing dog, but so much more awful to realize there was no dog. That poor little guy.
I've read numerous reviews that seem pretty upset about the episode. Ridiculous, they think. I felt it was a great character development episode.
I'm also seeing many noting it could be the end of the series, because the actors are sooo busy doing other things. Pffft. I'm hoping for many adventures to come.