[This is a review for Elementary season 2, episode 22. There will be SPOILERS.]
Since his introduction during the season premiere, Mycroft has come across as one of the more radical departures from Holmesian lore. This wasn't much of a surprise, initially, considering the rather inventive and rewarding way Elementary amalgamated Irene Adler and Moriarty into Sherlock's greatest love/greatest adversary. Mycroft's rather humble, somewhat secretive restaurateur was unlike previous incarnations of the character who was known to play up his mental acuity and deductive skills against Sherlock's in various – sometimes rivalrous – ways.
Still, with Mycroft's second appearance shortly thereafter, it was clear the elder Holmes brother was indeed up to something, although that something appeared quite nefarious. Those suspicions were ostensibly confirmed last week when Mycroft's reappearance coincided with Sherlock deducing that a French criminal organization was using Diogenes as their headquarters. And, to the writers' credit, Joan's kidnapping and the subsequent search for a missing banker Mycroft agrees to enlist his brother's aid in locating, does perpetuate that line of thinking long enough to make his order to "paint it black," followed by his vague admission to Joan that she deserves an explanation, come off as a tantalizing confirmation that not all is as it seems.
Elementary has pieced Mycroft together slowly, presumably for the purpose of demonstrating his prowess by keeping his true nature from one of the keenest deductive minds in existence. In that sense, 'Paint it Black' hinges entirely on that reveal, as much of the episode is spent listening to Sherlock deride his brother, and even attempt, in a particularly condescending manner, to encourage in Mycroft the most basic use of his observational skills. For much of the episode, Mycroft is willingly playing the stooge – at one point being referred to as a "buffoon" by Sherlock – so although 'Paint it Black' is almost exclusively one prolonged interaction between the siblings, the narrative is so focused on setting up the twist at the end, the immediate value of that interplay is entirely to the advantage of Mycroft, not necessarily the narrative at hand.
This is further compounded by the fact that Joan is away from the action, dealing with a steely French criminal determined to remind her and the audience what the stakes are, regardless her attempts to save his severely wounded cousin (and regardless the fact that the audience knows nothing will actually happen to Joan). The episode was directed by Lucy Liu, so keeping that in mind it makes logistical sense why Watson would be absent from the proceedings; but the dearth of her character is enough to rob some of the more profound moments between the brothers of their potential efficacy. It's one thing to have Mycroft pinpoint Joan's significance to Sherlock, and to have the audience hear and understand it, but it's another thing altogether for the characters (all characters) to be given that information to process a react to in ways that not only build their relationships, but also serve to enhance the foundation of the narrative. In essence, if Joan's the person Sherlock cares for most in the world, it's far more interesting if she knows that.
That's not to say that 'Paint it Black' wasn't a success, because, by and large, it was. Setting forth a clear goal of establishing the importance of Mycroft, and then reconfiguring his relationship with his brother was paramount. And the episode has certainly opened the door for a complete overhaul of their relationship – one that may now be even more contentious considering the prolonged deceit required to keep his true intentions and capabilities a secret.
What this means for the season's final two episodes remains to be seen. 'Paint it Black' generates a great many possibilities and mercifully resolves the Joan-as-victim angle so she can factor into the storyline as something more than a plot device. At any rate, there's a new dynamic at play between the brothers Holmes, and with any luck, the writers will have figured out how to capitalize on it without Watson getting short shrift.
Elementary continues next Thursday with 'Art in the Blood' @10pm on CBS.