Greg Dixon: Hotshot loses the plot

Benedict Cumberbatch and Martin Freeman star in the third series of Sherlock.

It's a mystery, wrapped up in an enigma hidden inside one of Mrs Hudson's cups of tea: what in hell has happened to Sherlock?

Last Saturday's series three premiere (8.30pm, TV One) was an absolute stinker, a monumental bomb, a complete loss of form. And I'm crushed.

In the first two series, Sherlock's creators Mark Gatiss and Steven Moffat had reinvented Conan Doyle's master detective with such panache and wit and style it was like some sort of magic trick. They had honoured the original while almost making Holmes and Watson seem like all their own work. It was a clever confluence of a cool aesthetic, excellent casting - I find it hard to imagine anyone topping Benedict Cumberbatch's insufferably anal reading of Holmes - and the best of modern television's visual gimmickry. I'd have said they'd created a modern television classic.

Well, I would have said all that until last Saturday.

Certainly Gatiss and Moffat had set themselves a pretty problem with The Reichenbach Fall, the stellar final episode of the excellent second series. After Sherlock's arch rival, the unbelievably arch, arch-criminal Moriarty, had put a bullet in his own head, apparently condemning Watson, Lestrade and Mrs Hudson to death too, Sherlock appeared to jump to his death to save his friends. Only he'd faked it of course, we knew that. But how?

Only Gatiss and Moffat could tell us ... but they seem to have no idea either. Instead we were given two hours of smart-arsery, in-jokes and plot conveniences but no actual plot.

Where previous Sherlock episodes have had a grand central conspiracy, this episode was a series of barely connected set-pieces very loosely held together by an afterthought of a storyline involving - huge yawn - terrorists wanting to blow up Parliament. This is a plot so old it's called the Gunpowder Plot.

The solution to the problem of how Sherlock faked his death was given not one but three possible answers, all of them, including Sherlock's explanation, totally unbelievable.

However, the first indication the episode was in deep trouble was the sudden, early and completely unwelcome appearance of pantomime farce involving Holmes pretending to be a French waiter when he re-appeared to a startled Watson. This was followed by an irritating set piece involving them being thrown out of ever worsening eating establishments as Watson kept hitting or head-butting Sherlock for pretending to be dead and for being such an awful shit.

Then there was the abysmal and half-hearted set piece with Sherlock and his parents (why?). There was also the awful set piece of finding the bomb on the train, which was (oh how hilarious) defused by turning off a big on-off switch. And I won't even mention the oh-so-convenient guy with the video of the bomber on the Underground.

Sadly, too, the performances of the leads - Cumberbatch and Martin Freeman as Watson - ordered on overplaying last weekend. It gets worse. I can report that in tonight's second episode, "The Sign of Three", which depressingly is even a bigger load of cobblers than the first episode, Cumberbatch and Freeman's performances drift over that border and into awkwardly sentimental. Mind you, to me all of Freeman's recent work seems a repetition of the same acting ticks; it's like Bilbo Baggins is helping Sherlock find a London bomber while Watson is footing it with Smaug.

However, what's more surprising is that in tonight's episode Cumberbatch's Sherlock pretty much apologises for being such an awful shit. It's embarrassing. It also doesn't ring true.

"Bollocks," bellowed Lestrade last Saturday at one version of the solution to how Sherlock faked his death. I knew how he felt.