Emotional resonance is not an element typically expected from a police procedural. The goal is usually to play up the theatrical aspects of the crime, to make it salacious or frightening and then depict the manner in which the perpetrator is brought to justice. Although many aspects of its design are procedural in nature, Elementary is fairly atypical when it comes to what properties it chooses to highlight and why. And because of that, it is capable of finding new avenues to explore within characters who are otherwise incredibly familiar.

As the second episode of a two-part storyline, ‘The One That Got Away’ is given a rather heavy narrative load that it manages to carry without overexerting itself. In addition to being the end of the short-lived Del Gruner storyline, the episode must also provide the audience with Kitty’s origin as well as make her inevitable departure with Sherlock a satisfying one. And despite the shifting of locales and timeframes from past to present, the final product succeeds in creating a coherent and meaningful end to Ophelia Lovibond’s time on the show.

With so many contextual elements in place – in addition to the last 11 episodes of the season – ‘The One That Got Away’ avoids becoming a typical “This is how they met moment,” when flashing back to the eight months Holmes was in London. Instead, Sherlock’s interaction with Kitty provides a greater understanding of their relationship as well as some insight into just how far she’s come since making the detective’s acquaintance. This, of course, happens amidst Sherlock’s own struggles with regard to his addictions and the apparent collapse of his personal and professional association with Watson that puts both characters in an emotionally precarious position, from which they manage to rescue one another.

All of the London scenes work well; primarily because they are concentrated on demonstrating what each characters wants. It is unsurprising that Sherlock wants Joan back, but settles for the sense of accomplishment he felt when teaching her his ways. Alternatively, since she is recovering from a much more harrowing ordeal, Kitty’s wants are exponentially greater. This leads to conflict between the two when Sherlock’s tutelage doesn’t result in hitting the streets and taking on a case as quickly as his new protégé would like.

Because this is a flashback, though, the stakes are relatively low – the audience already knows that Kitty accompanies Sherlock when he returns to New York – so the scenes can not only compress a few months down to a few minutes, they can also place an emphasis on the unspoken emotional bond formed between the two. The final flashback, when Kitty returns after a row they had a week earlier, finds Sherlock in an emotionally fragile state, which Miller depicts with great subtlety. The scene is the one described by Sherlock earlier in the season, when he addresses the heroin he’d taken from a crime scene and kept – either as a means of testing his resolve or for something far more damaging. And while the moment ends with Holmes throwing the packet into a fire, the emotional vulnerability that Sherlock displays is far more significant in terms of his character’s development.

So much of Elementary is about the recovery process and the ongoing struggles of maintaining it that the threading together of Sherlock and Kitty’s threads makes perfect sense. Although the two are dealing with two dramatically different circumstances – something Sherlock address when he confronts Kitty near the episode’s end – there is the sense that they share a unique attachment as people in the process of recovery – something that Sherlock could never really share with Joan, despite the intimacy of their relationship.

Even though the importance of Sherlock and Kitty’s relationship takes center stage, the thrust of the episode is naturally devoted to the detectives’ search for evidence that would prove Gruner guilty of crimes against Kitty and countless other women before and after. Much of the case involves trying to tie unsolved missing persons cases to Gruner, which appears to be fruitless until, through Joan’s confrontation with Del at a charity event, it is discovered he fathered a child with one of his victims before killing her. This realization certainly ties Elementary to the salacious part of the police procedural, but it also gives fuel to Kitty’s quest for vengeance and her decision to douse Gruner’s face with the corrosive nutmeg concoction from a few episodes back.

The move essentially puts Kitty on the lam, but it provides the episode a chance to say goodbye to a surprisingly rich and interesting character with a touching phone call in which she tells Sherlock she loves him. The moment becomes another great example of just how successful Elementary can be when it is determined to deliver moments that define who its characters are, while also recognizing the struggles they’ve overcome. And those struggles include Sherlock and Joan’s recent woes, which although they seem to have mended, may fully become a thing of the past, as the two partners have an opportunity to return to their customary arrangement.

Elementary continues next Thursday with ‘Hemlock’ @10pm on CBS. Check out a preview below: