Basically, this show needs to settle the hell down. God, was it fun at the beginning; it was inventive, believable, and immersive. The natural chemistry between the characters was a delight, and the writing was clever and funny (when appropriate). That was Season 1. It was great. Since then, the show's general quality has been on the gradual decline; however, there have still been flashes of brilliance from time to time over the past couple of seasons. But now the show has worked itself so far up its own backside – like some vulgar ouroboros – that it's become almost intolerable watching. Season 4 was so self-referential and unfocused that it felt like a spoof half the time, but then it would perform a complete 180 and get all serious on us, with the expectation that the audience should get all misty eyed when a character carks it or someone experiences some manner of personal hardship. This would be perfectly fine for viewers with certain insanities, or those who were so permanently struck by 'Sherlock''s glistening first impression that they're oblivious to how far they've followed the show into its own bullcack, but for the rest of us who appreciate consistent style and careful execution of tone, it's unimmersive at best and painful at worst. I'm telling you, Mark Gatiss and Steven Moffat have written these screenplays schizophrenically. The only way to enjoy a narrative of this kind would be to possess an unrelated set of mood swings that miraculously synchronised with Gatiss and Moffat's wild shifts in tone.

I honestly don't know what they were going for here, and how they thought it was going to work. God knows how someone's supposed to direct this nonsense. Hats off to Rachel Talalay, Nick Hurran and Benjamin Caron from trying; I know I won't be judging their abilities based on what I've seen here. Thankfully they don't seem to be bearing the blame for this disastrous season, as all the criticism I've seen so far has instead been falling on the heads of Gatiss and Moffat exclusively. And rightfully so, really, because if a film is viewed as a train, then the writing can be viewed as the rails, and the rails in Season 4 were dodgy as anything, and ultimately these episodes were a wreck. As a writer, there must come a time when you stop believing in yourself, and start actually being critical again. You should have a doubt or two; it's good for you; it makes you better. Gatiss and Moffat seem to routinely skip over this step in their journey as writers, though, and continue in blissful misinformed confidence. And it reflects so horribly in their work on this occasion. The characters are so pompously written, primarily communicating in phony wit, which they each appear to enjoy far more than the audience does. Almost every exchange pretty much amounts to a session of smarmy backslapping and meat-beating. And I could probably put up with that (just) if the show was still at its high-points, but it's not. It's the worst it's ever been; it's like listening to someone gloat over an achievement so long past it might as well have belonged to a different person.

A key aspect that may be affecting the show's execution of the basics may be its obvious desire to keep 'going big'. It's becoming clear that it's simply not enough for the show to just have a nice, self- contained episode. Nothing is allowed to just be its own story; it has to be part of a larger arc, and that larger arc has to be tied into another arc, and those arcs have fit into an even larger mother-arc, and it just goes on and on, inexorably, getting bigger and bigger. It's an arc- blob that keeps feeding on promising story threads, killing and absorbing them for sustenance. But one day one day there will be no good ideas left for the blob to devour, and 'Sherlock' the blob will be left with nowhere to go. It will be stranded and unfixable, its biology a convoluted mess. A grotesque testament to a series gone wrong; a far cry from the fine specimen it once was, before its caretakers thought they could play God, and fecked with its genetics so severely that its hunger for the 'epic' could not be satiated, and its digestive systems could not process or filter out the vast intake of stupid ideas.

Episode 2, "The Lying Detective"– in spite of its silliness and melodrama – was an episode that felt a little more like a focused, simplistic, enjoyable isolated tale of problem-solving. But whatever maturity and restraint it had was blasted out its back end with a ridiculous ending that over-involved a deceased character who was never very interesting in the first place, and introduced a new threat – the biggest one of all! – in the lamest way possible.

This season was just messy. I couldn't bring myself to enjoy it without the feeling of undermining my intelligence in some way. My opinion of the show also wasn't improved by the fact that I interspersed my viewing with episodes of Stewart Harcourt's superb detective drama, 'Maigret', starring Rowan Atkinson. I might review it in full one day, but for now, I'll just prescribe it as the perfect remedy for 'Sherlock''s latest batch of nonsense.

It has special qualities – sophistication, maturity, atmosphere, cleverness – that 'Sherlock' once had, but has since lost, causing fans of the show and the genre to all be poorer for it. The show has lost its integrity, and also become unbearably self-congratulatory in the meantime. It needs to come back down to earth, get its act together, return to the basics, and rediscover what made it great in the first place. I fully intend to support it in its recovery, but it needs to first admit that it has a problem.