One of the scariest episodes of the show, 'The Hound of the Baskervilles' is brilliant, with the horror of the hound stalking John across the lab - and Russell Tovey's character Henry Knight at home - being by far the most captivating scenes. It's also a fascinating look into the mind of a frightened Holmes, as he starts questioning everything around him, pushing John away. As is the standard of the show, the direction is excellent, with the chilling white laboratories contrasting nicely against the murky woods. The twist of what the beast is, is typically Gatiss, and likewise, the small threads that tie up throughout the episode, such as the owner of the luminous rabbit are wonderfully handled. But more than anything 'The Hound of the Baskervilles' is a rattling episode for the show; it shakes up its lead characters and their relationship, takes Sherlock out of his London comfort zone, and throws an enemy into the thick of the action that's almost unseeable; it's really a test of how great this show can be, and though it's not the best episode, the cast and the writing surpasses that test with flying colours. It's an intriguing mystery tale, perhaps capsized, some might say, by an anti-climactic bombshell of a ending. But nevertheless, it's a fantastic plot, and a bone-chilling piece of television.
