The season (series?) finale of Sherlock was difficult to watch. It had a dark, disturbing element to it, and for a time, I was afraid we would lose another beloved character.
The following contains spoilers in the form of the entire plot. I usually try to avoid spoilers, but in this case, it can't be helped.
As we learned in The Lying Detective, the Holmes brothers have a little sister. Where Sherlock is a high functioning sociopath, Eurus Holmes is such a dangerous psychopath, older brother Mycroft kept her hidden away in a secure island facility and told their parents she was dead.
But little sister isn't as secure as he believes, and after she shoots John Watson, Sherlock learns of her existence. Rather, he rediscovers her existence. He had repressed memories of her after suffering a childhood trauma at her little hands. All grown up, she's more dangerous than she had been as a child. And this time, she has help, including Moriarty.
That's right, the Moriarty thread is finally revealed and brought to an end. But it's a game that turns deadly as Sherlock, John, and Mycroft are forced to solve Eurus' deadly puzzles. And bodies are dropping.
What I didn't like about the show:
Certain parts weren't plausible even though the show's creators have been prepping us for such—I hate to say it because I love this show—absurdity. Despite that, the tension was high-squared as the three men struggle to find solutions while dealing with evil and save lives, often their own and people who are dearer to them than they had realized. It was so tense at times, at one point I had to walk out of the room.
The rest, I loved. I've always enjoyed the banter and sibling rivalry between Mycroft and Sherlock. Familial relationships are brought out even more in this episode with the addition of a few home movies, old memories, and their sister. Despite Mycroft's claims of protecting Sherlock in the interest of national security, we see there is little he won't do to save his baby brother, even if it means protecting Sherlock from their little sister.
I loved that and that in the end, Sherlock extends that same protective nature toward his sister. Instead of being satisfied with locking her away as Mycroft had, the man who can't, or refuses to, form close relationships (and now we know why) gives Eurus the one thing she always wanted—him. His time, his attention. At the end, he arrives at her newly reinforced cell and reaches out to her as no one can with the one passion they both share, the violin. It was forgiveness at its best (meaning I forgave Gatiss and Moffat for the rest of the show.)
For all its psychopathic tension, this episode had a great ending. Unfortunately, The Final Problem felt a little too final, and I wonder if there will be a season five. We'll find out next year, I suppose. In the meantime, I'll stream past episodes starting with The Sign of Three. I could the delusion of happily ever after. And I'll keep an eye out on Amazon for Mycroft's umbrella. That's a handy little thing.