These adaptations of Conan Doyle stories made during the 1980s have one really big asset and one really big drawback: the asset is Jeremy Brett as Sherlock Holmes. Brett plays Holmes as an intensely tactile, active man, with facial expressions of almost startling ferocity. He has a peculiarly bold sort of physical presence which forces the viewer to think, "yes. This is Sherlock Holmes" (at least for the duration of the episode). It was particularly well done in this episode, with his various drug addictions leading him to be sickly and weak at the commencement of the story, and in full-on virtually-unhinged-by-genius mode at the end, but with both parts being played with the same sort of angry joy at the world.
The one major drawback of these adaptations of Conan Doyle stories is quite simple: everything else. It's not that the episodes are bad exactly, but everything else is playing on a completely different level to Brett. Edward Hardwicke is playing his Doctor Watson as if Jeremy Brett was acting like a normal person acts in a BBC period drama - as if Brett had no real intensity. He's not a bad Watson, he's actually quite good, but he and Brett are just never on the same wavelength. And for some reason, everything else about the show seems to follow Hardwicke's cue, rather than Brett's. It's almost as if we get two different versions of the show being played at once - Hardwicke's refined, regular BBC prestige production, and Brett's madman freakout extravaganza. Either one by themselves would be a pretty good show, but together they seem... weird. Not bad, it's still quite an entertaining show. But still... tonally weird.
But to the episode proper. The Musgrave Ritual is a stupid plot, and it is impossible to disguise the central preposterousness of the premise. The idea that someone would hide the secrets of buried treasure as a riddle in a family ritual just makes no sense. Why did this ancestor do this? Was he just really bored one day ,and thought to himself, "I'm going to write the most awkwardly worded riddle imaginable. It isn't going to have two meanings, it's just going to be goddamn retarded"? Why could nobody solve it until Holmes came along? I know somebody says, "we've tried for years and years to work out the riddle, it's just nonsense," but that doesn't excuse these characters from being utter morons. I mean, goddamn, their goddamn butler managed to solve the riddle working surreptitiously at night. NOBODY in the Musgrave family could solve the riddle, for all the hundreds of years it's been recited? That makes no goddamn sense.