I would like to engage in a real discussion about s4. I found the suspension of disbelief demands too high in TFP. Secret crazy psychopath sister locked away since early childhood, convenient piracy of randomness boat in time for secret sister's murder maze, the Murder Maze, magic teleportation to Musgrave with John chained in well, silly graves conveniently solve song puzzle... oh and I forgot about the prank at Mycrofts house. Actually that was sort of believable from Sherlock. But thoughts?
I’m not sure any of these things on their own require any more suspension of disbelief than other plot points in this series, to be honest with you. But I think I know what you mean.
You’ve raised a lot of issues, but let’s talk about the problem of Eurus.
Secret crazy psychopath sister locked away since early childhood doesn’t really require that much more suspension of disbelief than we’ve already been primed for, and that may be the problem. We know there’s a third Holmes sibling who Sherlock never mentions and the Holmes parents don’t invite to Christmas. It isn’t actually that far out of the realm of possibility that she’s the smartest of them all.
They give us an explanation for why she’s locked away: she kidnapped and killed a child, burned the house down, and was threatening to kill Sherlock. She was institutionalized as part of treatment and to protect others, something that happens when a child is uncontrollably violent. I don’t think that’s too far out of the realm of believability.
Her superskill of controlling the people around her i actually like, as it’s a call out to Arthur Conan Doyle’s belief in mesmerism. It could have been more subtle, but it was wrapped up in an action-adventure film, so I think it comes off more heavy-handed than it could have.
The existence of Eurus answers a lot of big questions about Sherlock himself. We’ve been asking all along why Sherlock is determined to see himself as a sociopath when it’s clear he isn’t one: well, now we know why! It also answers the question about why Sherlock turns to drugs, and why he’s so driven to solve puzzles, particularly crimes. He’s reliving that key moment where solving a puzzle would have saved the life of someone he loved, and if he’s not busily doing that, the inside of his head is a fresh hell.
I think the essential problem with Eurus isn’t so much Eurus herself, but the fact that “extra-smart people exist and are terrifying” is the go-to trope for this show. We’ve got Sherlock, who is dazzlingly smart, and we’ve got Mycroft, who is extra-dazzlingly-smart. Then we get Jefferson Hope. Moriarty. Irene Adler. Mrs Holmes. Magnussen. Mary Morstan. Culverton Smith. Even, possibly, Mrs Hudson. And finally, Eurus. There’s just too many of them.
This problem is, I think, a sign of limited planning and probably insufficient brainstorming. When you don’t plan to generate enough ideas to choose between, you tend to reach for the same solution to a plot problem over and over again because it’s sounds so great every time. Moriarty is a threat to Sherlock because…he’s smart in the same way Sherlock is. (So creepy!) Irene Adler is a threat to Sherlock because…she’s smart in the same way Sherlock is. (Forcing him to re-evaluate himself!) Magnussen is smart enough to keep a mind palace full of undocumented facts, just like Sherlock does! Culverton Smith is so smart he can be a serial killer hiding in plain sight, acting one way but secretly being something else (just like Sherlock!). Mary is sweet and nice, and you think she’s going to be a normal person in the mix, but she’s actually super-smart and dangerous, just like Sherlock! Individually these are great story decisions, but taken all together, the repetition of the theme undercuts them all, and fundamentally undercuts the final antagonist.
Eurus is one of the few characters who actually needs to be super-smart in the same way Sherlock and Mycroft are, but uncontrollably more. She is the Ur-smart person, the one Sherlock is both emulating and fighting against his whole life. But her existence is diluted and made to seem redundant because of all the other super-smart villains running around who faintly resemble her. They wouldn’t have had to make her quite so extra if Sherlock-like villains hadn’t been a dime a dozen already.
