This final episode of Sherlock is going to have fans theorizing endlessly until series three – and god knows when that’s going to be. The Reichenbach Fall is an abrupt return to form after a slightly slower second episode. As with series one, the middle episode was a little weak, and felt like mere filler between the astonishing first and third episodes.

Spoiler Alert

Episode three starts with John Watson back in the therapist’s chair, an about turn back to the first-ever episode. Only this time, it’s not the absence of war that is troubling him, but of his best friend Sherlock, who is dead. Thus begins an utterly compelling episode from start to finish, not least because we’re waiting to find out just exactly how the enigmatic detective meets his end.

They managed to cram a lot into this episode, though none of it felt rushed or unpersuasive. The skill in the writing should really be lauded for its ability to deftly communicate with the audience without patronising us or underestimating our intelligence. This episode cranks out red herrings and curve balls like no other, and though little hints are dropped all along, it never fails to surprise with shock developments and sudden twists, with a pretty high level of tension maintained throughout.

One sequence which struck me was Moriarty’s narration of “Sir Boast-A-Lot”, cut into the unfolding of the story in reality. Sergeant Donovan and Anderson are brought back from episode one to catalyse Sherlock’s fall, and it all feels as if it’s neatly come full circle. Even Molly, Holmes’ helpless admirer, largely side-lined and ignored since the start, comes into the foreground and (I think many people will agree) will likely play a major part in explaining the mysterious resurrection of the hero.

Over this series we’ve been seeing, largely thanks to Watson, the softer side of Sherlock emerging. In this one, we see actual tears. That shocked me even more than his body smacking the ground when he jumped off the roof of the hospital. Finally, we see some real emotion from the icy prodigy. Again, the writing needs to be credited for creating this highly touching and candid bond between Holmes and Watson. Martin Freeman does a particularly worthy job of portraying the determinedly stoic, soldierly exterior that barely conceals Watson’s marshmallow heart.

So now all that remains for us to do is wait. Wait and feverishly guess at just how Sherlock did it – how did he jump off the top of the building and survive without a mark on him? The cyclist, Molly, Moriarty, the recycling truck, the screaming girl earlier in the episode … I’m sure they all have a role somewhere. I was infuriated when the episode ended, but what better way to ensure that I will sure as hell be watching when series three comes around.