Here's another example of Conan Doyle's stories being twisted just to add length and gratuitous violence. The original story had no real violence, just a temporary assumption that violence had taken place. Lord St. Simon, at the end, exits the scene with stiff, chilly dignity, to resume his search for a rich heiress, because there has been a discreet hint that his finances are a little unstable.

The televised version takes this discreet hint and uses it to turn St. Simon into a black widower, ruthlessly seeking out rich heiresses, and using up their money at an extraordinary rate. He has his first wife killed on their honeymoon, then hires to killer to be his groundskeeper. He has his second wife declared insane (something that used to happen all too easily in the real world), transferred her from the asylum to a hole in the ground on his estate, presumably to save money, then had the marriage annulled. (It didn't seem to occur to the scriptwriter that if the marriage had been annulled, then it had legally never taken place, and he would have had no right to her inheiritance. Perhaps he annulled it after he had used up all her money, but then the lady's sister could have taken him to court.)

Hattie Doran, the last victim, who was supposed to be a strong, free-spirited lady, ends up your typical, idiotic lady in distress. Having been told by St. Simon's former mistress the complete truth of his goings on (before said mistress gets herself killed by you-know-who) she blithely goes off to confront St. Simon--alone. Even if she didn't quite believe the mistress's tale, even a tiny bit of doubt should have prompted her to take along a back up. Her real husband springs to mind. What was he thinking of, letting her go off alone like that?

St. Simon's second wife, who held on to her sanity for seven years, plotting her husbands demise, seems to be the only woman, aside from Irene Adler, that Sherlock really admires fully. (Escorting the lady to a concert! For him, that's practically tantamount to an engagement!)
At the end, they say that St. Simon's estate is turned over to Lady St. Simon, the second. If the marriage had been annulled, what right would she have had to it? It should have gone to the other members of his family. Saying that it was compensation for those seven years in a hole is a nice idea, but the law doesn't work that way.

One really nice touch that I found in this episode was when St. Simon went to look at his second wife and, not seeing her in the hole, whistled for her, as though she were a dog. That really summed up St. Simon's character.

This altered storyline was interesting and exciting, but as a Sherlock Holmes reader, I was disturbed by the liberties the scriptwriter took. Not to mention that very peculiar sub-story about Sherlock's weird dreams. What exactly was the point in that?