ok just really quick i know that i'm a person who doesn't like when people try to theorize what will happen in episodes but i have to right now so if you're one of those people don't look at this
The tagline for "His Last Vow" is "Someone will have to die," right? I don't think someone will die in this episode. I think the cliffhanger will be a choice of who to save.Â
Magnussen is the King of Blackmail. In previous episodes, there have been nods to popular movies, and in "The Empty Hearse" the whole episode was centralized around the 5th of November, like in V For Vendetta. At the start of "The Sign of Three" there was a small reference to The Dark Knight. Considering that the first episode's referencing was a lot heavier than the second's, and the tagline for this finale, I really think that Magnussen will end up blackmailing either Sherlock or John into having to choose Mary or their counterpart to save.
I think it would be John to choose because, like he said, these are the two people he loves most in the world, but on the other hand I think it'd be Sherlock to choose because he'd either save his best friend or his best friend's wife and John would probably be angry like Harvey Dent was in The Dark Knight that he was the one to live.
And actually, now that I think about it, it could be Mary to choose who to save, considering that she'd received a text from an anonymous person in "The Empty Hearse" to drive her to save John with Sherlock's help.
I really don't know who exactly it would be to choose who to save, but this is honestly what I'm thinking. And I'm probably wrong, but I just had to get this all down.
