Sherlock’s former sponsor Alfredo has gone missing, which carries with it the worry that he’s relapsed into addictive behaviour. Sherlock is then contacted by Oscar, his erstwhile drug buddy, who featured a few weeks ago. Oscar wants Sherlock to find his sister Olivia, also an addict, and just as Sherlock is about to dismiss the idea Oscar reveals that he knows where Alfredo is, and that he’ll trade that information for assistance in finding Olivia.
Given the background, Sherlock’s search for Olivia inevitably takes him back into the world of heroin addiction, which is not a comfortable place for him to be, although he reassures Watson that he won’t be tempted. As it happens, though, Oscar already knows what’s happened to Olivia, and his purpose has been nothing more than to show Sherlock that he’ll never escape the addict’s lifestyle, and to try and drag him back into it. Even allowing for the fact that Oscar is himself an addict, this is remarkably cruel. And what makes it worse is that Oscar is right: Sherlock brutally assaults him, heedless of whether he lives or dies – and that remains unclear at the end of the episode – and then, it is very strongly hinted, relapses into heroin use. There’s a harrowing final scene in which Watson tells a withdrawn, uncommunicative, dishevelled Sherlock that his father has found out what has happened and is on his way to New York.
‘A Controlled Descent’ is probably the best episode since the first half of the season, working on multiple levels: the plot itself is compelling; it builds on the way in which the season has shown Sherlock to be open to the idea of friendship; it reintroduces him as a heroin addict, which the show has never entirely lost sight of; and it raises the prospect of exploring the relationship between Sherlock and his father, something else which has been hanging over the show since the start. All in all I’d say that this has been the best season of Elementary so far, particularly the sequence of episodes leading up to the departure of Kitty; and the news that John Noble, one of the best actors working on TV today, has been cast as Sherlock’s father (and as a regular rather than a guest) is a welcome reaffirmation of the show’s commitment to keeping the quality level high.