Only just found out that SHERLOCK is back on PBS (so out of the loop I am) so I have not yet seen the return/premiere. Just wanted to get some goofy theorizing out there before I watch the new eps…
*SPOILERS* from "The Reichenbach Fall" follow!
The end of this second series is so *obviously* an homage to the original second film—duh! I mean, Sherlock goes and sees the doctor (Molly) before confronting the threat to his human friends. In that meeting he engages the doctor in a mind meld (not shown, possibly a *sexy* mind meld). Then he faces off w Moriarty and finds himself in the no-win situation. He shares his last moments with (Captain) John and then dies, saving them all.
John will think that Molly's odd behavior—involving the manifestation of a second, familiar, personality, with an offputting selfish attitude, eager to share incisive observations that while accurate, come off as rude and thoughtless—is no more than just a strange brand of mourning. But when Mycroft comes to him, seeking Sherlock's Katra in Watson's mind, he will realize that Sherlock must have melded with Molly before his fall.
Then it will be up to John and Mycroft, w some help from Lestrade no doubt, to get Molly and Sherlock's rebuilt, resuscitated (thanks to Baskerville Genesis tech), comatose body back to Vulcan to return Holmes's Katra into a proper vessel, bringing him back to boring old life.
And of course, the Sherlock we saw at the end of "Fall" was *Ambassador* Sherlock from the original timeline.
Keep on keepin on~
P.S. Take a look at the captains' final words over their friends…
Kirk: And yet it should be noted, in the midst of our sorrow, this death takes place in the shadow of new life, the sunrise of a new world; a world that our beloved comrade gave his life to protect and nourish. He did not feel this sacrifice a vain or empty one, and we will not debate his profound wisdom at these proceedings. Of my friend, I can only say this: of all the souls I have encountered in my travels, his was the most… human.
Watson: You... you told me once that you weren't a hero. Umm,there were times I didn't even think you were human. But let me tell you this, you were the best man, the most human... human being that I've ever known, and no-one will ever convince me that you told me a lie, so there. I was so alone, and I owe you so much.