Sherlock: So, how did the great detective fake his own death?
In the end, it all came down to a squash ball concealed under his armpit - had anyone predicted that?
Nearly two years has passed since the first broadcast of season two's finale The Reichenbach Fall, in which Sherlock (Benedict Cumberbatch) appeared to jump to his death from the roof of St Bart's Hospital while Watson (Martin Freeman) looked on in horror.
That means Sherlock's febrile fans have had nearly two years to speculate on the significance of the various plot leaks and clues. How exactly did Sherlock fake his own death? What has Watson been up to since? Would Sherlock finally act on his sexual tension with Molly? Or, better still, with Watson?
The greatest satisfaction of this thoroughly satisfying season opener was confirmation that Sherlock co-creator Mark Gatiss (who penned the episode) knows us fans better than we know ourselves. He dangled an easy answer to the fake death conundrum in front of us, then, just as we were realising that the outcome is never as good as the anticipation, he snatched it away again and replaced it with something better.
The fans even had a role in the episode, embodied by an obsessive Sherlock Holmes conspiracy theorist and a fan-club member played by Sharon Rooney from My Mad Fat Diary. She was one of several cameo treats, including Derren Brown (a man after Sherlock's own heart) and Cumberbatch's own mum and dad as Sherlock's parents. In an episode full of twists, the news that Sherlock has parents and didn't just spring into existence as a fully formed entity was probably the biggest surprise of all.
With a resolution for last season's cliffhanger revealed (sort of), it was time to get back in the crime-solving swing. "I need to get to know the place again," Sherlock said. "Breath it in, feel every quiver of its beating heart."
Cue lots of London-loving skyline shots and a mystery set within the city's own cardiovascular system, the London Underground. The Tube is so rich in ghost stations, wartime secrets and general London lore, it's a surprise it's taken Sherlock this long to get around to it.
As for the significant others in Sherlock's life, it was a relief to see that despite Moriarty's play on his sentiment, Sherlock remains his emotionally stunted, semi-sociopathic self. A romance with lab assistant Molly would have felt untrue to the character and his attempt to reintroduce himself to Watson was a tour de force of insensitivity. With Sherlock, you can never be entirely sure that a warm, fuzzy heart really does lurk beneath his cool exterior - it's what continues to make him so compelling.
Perhaps the only disappointment was the confirmation that Moriarty really is dead-dead (as opposed to Sherlock-dead). Andrew Scott's giggling super-villain has been almost as much fun to watch as the great detective himself. We did, however, catch a partial glimpse of Sherlock's new nemesis, and eagle-eyed Borgen fans might have recognised a familiar pair of eyebrows.