‘Mr Holmes, they were the footprints of a gigantic hound!’

Let’s be honest, casting Russell Tovey, best known as George, everyone’s favourite werewolf on Being Human, in the Sherlock episode ‘Hound of the Baskervilles’ was either going to be a stroke of genius or an act of utter madness. Aside from the occasional snicker as he crunched about in the forest, it was good. There was the occasional urge to try and resolve the discrepancies between the two shows, but Tovey quickly established Henry Knight’s character as distinct.

Other than that bit of controversial casting, this was a good episode with the occasional terribly, terribly convenient bit. Writing is all about unlikely convenience of course, but the point is to stop the viewer/reader in rolling their eyes and exclaiming, ‘How convenient!’

Henry Knight was tragically orphaned on the moors many years ago, when his recently widowed father got torn apart by a monstrous beast during a father-son walk. This, obviously, left Knight with more than a few issues. Issues that come to a head after his therapist sent him back to the moors where he found the, aforementioned, footprints.

This is, of course, the updated Sherlock Holmes, so the superstitions evoked aren’t those of demon dogs and curses but of conspiracy theories and genetic experimentation. There is a military research facility on the moors, a Porton Down with more monstrous hounds – and the theory is a beast escaped from there to ravage the countryside. It maps perfectly. I did give Sherlock rather a hard time over what the did to Adler last week – which I still hold are true, no matter what Moffat tweets as law* – so credit where credit is due. This was excellently done.

After a brief visit to the military base – where the personnel don’t officiously check the ID like they do at every other checkpoint in the entire world, since ‘Mycroft practically is the British government’ – they head out to the moors where they see the angry puppy.

Or at least Knight and Sherlock do. Knight is shaken, but thrilled to have his story confirmed. Sherlock’s reaction is a bit more complex. On the surface he is afraid, uncertain and angry at himself for both reactions. He is, after all, Sherlock Holmes. He does answers, not questions. Yet it is almost like he – who had earlier been pestering Watson for drugs to relieve his boredom – is high. He is sweating, his hands are shaking and he is manic. He even has a row with his best friend, sending him humphing into the night.

He might not like the way seeing the dog made him feel, but feeling anything so strongly is like a narcotic. Something to focus on, to stop his brain noticing everything else.  Watson has more to do this week than last, but this week Holmes brain is front and centre. We see it work.

The narcotics connection is one Sherlock comes to himself the next day, deciding that he must have been drugged. He’s almost right, but the reaction to emotion wasn’t just the drug, there’s a lot more truth to uncover. The truth about hounds and liberty and, at the very end, death.

After the mixed feelings of ‘Scandal in Belgravia’, this week was pure, guilt-free enjoyment. Sherlock being Sherlock, and John always underestimating exactly what that means. There were a few, as mentioned, very convenient moments but on the whole it was just an hour and a half of fun, clever television.

Ending with a quick glimpse of Moriarty in a cell. By the look of things, something has gone very, very wrong since last we saw him. He is looking a bit more deranged than usual.