Sherlock 4x03 "The Final Problem". SPOILERS.
A fascinating thing has happened. Moffat and Gatiss created an episode that was bad in so many ways. Yet I was emotionally engaged on the highest level and, in the end, I'm ready to forgive almost everything.
It's obvious that the plot wasn't planned all along. There's no trace of "I know exactly what Moriarty's going to do next". You can't convincingly explain how Sherlock could have forgotten he had a sister. Mycroft would never let Moriarty speak to Euros in private. The story doesn't make much sense even if we consider only that particular episode. Euros' powers are magic. Sherlock keeps playing the game even after Euros breaks the rules and kills all three Garridebs. No one was able to find the well and save little Trevor. It's sad to watch the series' world fall apart because the writers want it bigger, darker and more dramatic but can't keep it from breaking laws of logic.
I believe Euros is what we call "jumping the shark". She's worse than the worst villains and more clever than Mycroft. The whole Sherlock's past is rewritten to make her the reason for him being who he is. And I don't like it. It was a better story when there were just two brothers and the younger one wanted to be as smart as the older one. (He didn't realise he was.)
Moriarty's part (I didn't expect to be so happy to see him! It turns out, if he faked his death, I wouldn't really mind) is a disappointment because it's so small. Seriously, few recordings and that's all?
And now what I loved about the episode. The fact that Sherlock was desperate to save the girl on the plane proved that he was no longer "a detective who'd solve a mystery of your death", but, like John, "a person who'd save your life" or at least try. While Mycroft is focused on not hurting more people and gives up on her - he's always thinking a bigger picture and often represents the "pure reason" - Sherlock is always about individual people: his clients and friends. It's the biggest difference between them and I liked how it was shown.
We've also seen the difference between Mycroft and John. Mycroft might be the government, a person who holds great power and comes up with genius ideas, but he does it from his office. In "The Final Problem", he's out of his comfort zone and both his and his brother's lives are in danger. In those cells, he's incapable of making a full use of his brain, and, sometimes, is just useless. John, on the other hand, might have acted out of character in previous two episodes, but here, back at war, proves he's a soldier capable of dealing with the toughest situations. He stays calm and focused. The scenes with Euros telling them to shoot the man, or when Mycroft tries to make it easier for Sherlock to shoot him, are excellent character studies. Despite not believing one of them would actually die, I had my eyes glued to the screen.
Some scenes showed us similarities and differences between Sherlock, Mycroft and Euros, and that's why I can't say I hate the whole concept (I just think it would worked better if it was done differently. Maybe in Sherlock's mind palace. Maybe as an alternative). We can see that the "pure reason" was alone, while both Mycroft "the Iceman" and Sherlock managed to become valuable members of the society and develop some relationships: very deep for Sherlock, less deep for Mycroft. They built their lives and found their places in the world. Sherlock proved to be a greater man than Mycroft in the end, which is why he became the legend. But also Sherlock was the one who finds a way to communicate with Euros: music. Isn't it a great way to make use of the fact that Sherlock plays a violin?
The last scenes were a great idea: coming back to the very first episode and wrapping up the story about how Sherlock Holmes and doctor Watson became the legend. I'd only prefer if it wasn't just Mary's voice telling this (seriously, how many dvds had she recorded?), but everyone close to Sherlock and John: Lestrade, Mrs. Hudson, Molly, Mycroft, Anderson and Mary. Everyone says a line about them, as we see them back on 221b, solving crimes. It's the best ending I can imagine as it sums up the series. It was a fantastic journey from the very first episode. It might have lost realism (Mary's overdramatic death turns out to be true), witness (the cases in first two season were best), scale and logic from time to time, but in the end, "Sherlock" told us a story about a clever man who becomes a good man. The man we know from Arthur Conan Doyle's stories. The hero. Sherlock Holmes. And for that, thank you, Steven Moffat and Mark Gatiss.