"Watson! This is no time for humbugs!"
This is an interesting choice of episode for a season finale- the short story by Conan Doyle, I recall, works rather well as a detective story with the twist being particularly effective. While there are plenty of twists and turns here, and the episode functions rather well as a mystery, there is a lot more going on here.
The structure, as is sometimes the case, is a little odd, with a lengthy series of opening scenes, with all dialogue entirely in unsubtitled Italian leading us, like Lestrade, to suspect that these stereotypically excitable Italians (including one Marina Sirtis) have some connection to the Mafia- after all we, unlike Lestrade, have probably seen The Godfather, and there's some clever misdirection in getting us to think of Senor Venucci as a kind of Don Corleoni figure.
But I think there's something else going on. All these excitable characters, wearing their emotions on their sleeves, are intended as a contrast with Holmes. For this is a superb episode for examining Holmes as a human being, and Jeremy Brett gets to act his talented little socks off.
The friendship between Holmes and Watson on one side, and Lestrade on the other, is superbly captured. There's a real rivalry, yes, but also a mutual affection, although of course one that can never be stated. The dialogue, the looks, Lestrade's tolerance for Holmes' quirks, all are superbly written, acted and directed. And that final scene, where Holmes awkwardly accepts Lestrade's fulsome praise, hints at the obvious supposition that Holmes may not be entirely neurotypical, without being reductive about it. Simply superb.
