It was the question on everyone’s lips: why did Watson feel the need to grow that moustache? Oh and also, how did Sherlock manage the whole roof-jumping, death-faking thing in the second series finale two years ago? This long-awaited and much-hyped opener to series three promised to reveal all. And for the most part it did. But did it match the brilliance we became used to in the first couple of series? That’s up for debate.

At the beginning of the episode, Sherlock is ‘dead’. Watson is grieving, but also preparing to propose to his new(ish) girlfriend. Mrs Hudson is angry at his lack of contact, thrilled by the news of his upcoming nuptials, and once again surprised by his sexual orientation. Anderson has apparently turned into one of those people who make YouTube videos about how Sherlock threw himself off a building without dying. (All very meta, I know).

Ah yes, the roof-jumping. Finally, we were going to find out what actually occurred behind that lorry full of bin bags. But not, it seemed, until we’d sat through a couple of red herrings. It’s a shame that they were red herrings, because I quite enjoyed the plan that hinged on Derren Brown hypnotising an already-concussed Watson. In the end, though, Sherlock survived with a giant blue bouncy castle, a dead ringer (literally) and a couple of dozen homeless people. That’s what Sherlock tells a slightly deranged Anderson, anyway. As for the moustache? Still a mystery.

Back to the present, and Sherlock is being tortured in Serbia, until Mycroft casually steps in and summons his brother back to London. The reason is an imminent terrorist attack on the capital. But that can wait. First, we need a few emotional reunions. Except that Sherlock doesn’t do emotional. He prefers dressing up as a French waiter and crashing a marriage proposal: much more dramatic. As always, it was Sherlock’s endearing lack of social and emotional tact that made for the most entertaining moments of this episode. Where plot was concerned, though, it fell short.

The trouble was that this episode felt aimed towards diehard Sherlock fans, and less towards people who just like watching good TV. Time was spent poking fun at fangirls when it should have been used to move the story along. As a result, the Guy Fawkes-inspired plot to blow up Westminster using the Underground felt rushed and was resolved all too quickly and simply. I’m now wondering how many films and series of Homeland could have ended sooner with the knowledge that bombs have ‘off’ switches. Overall though, it was an enjoyable episode, with the usual razor-sharp script and top-notch acting we’ve come to expect. Now that Sherlock is firmly installed back in Baker Street, the upcoming episodes will hopefully be back to usual form.

Just one more niggle: I could have done without the edgy shots of the Underground. The Tube is not that cool. And it’s never that empty.