Previously on Elementary: Blood Is Thicker.

Following a scenario paying homage to The Problem of Thor Bridge, Sherlock and the team discover that Lucas Bundsch may not have shot Samantha Wabash, but he sure as bullets killed her sister. The hunt for the serial killer is on.

Oh my stars, this episode is so well done! And by that, I mean wonderfully creepy. Setting up Joan and Sherlock as the killer’s direct adversaries — instead of just trying to stay under his radar and finally tripping him up — is a great twist and provides a flood of tension that works really well.

What else is great is seeing Captain Gregson so protective of Sherlock and, by extension, Joan. He’s willing to fight for them to stay on his team — he’s scandalised and worried at the thought of Coventry giving out their address to a suspected killer, too. At the same time, and that’s what’s brilliant about his character: he calls Sherlock out on his shit as well, while defending him in front of outsiders, because that’s what friends do. He tells Sherlock, in no uncertain terms, that he is taking a huge risk letting him in on these investigations. But he keeps making that decision because it’s the right one, and because, who knows why, he likes his consulting detectives, and he would fight for them a hundred times over. Except when their involvement so dramatically impacts a case that he cannot justify keeping them on. Once they’ve found a way to work around, that, however, they’re back on. His speech at the end of the episode is a powerful reminder of that. Wording it like this — telling people to put up with it or leave the precinct — may not have been wise, and I’m not sure if it won’t lead to more problems (at least with Coventry) down the line, but it was a good moment for his character. In the end, keeping New York safe is what he cares about most. He has no trouble putting his ego aside to get help from someone who’s smarter than him, so he expects other people to do the same, because it does not mean that he values his own department any less.

Another thing that had me squee: seeing Joan taking Sherlock apart for being a prick. Sherlock counters by pointing out that his behaviour towards Coventry stems from his own anger at himself for “undoing Samantha’s sacrifice,” and that may be a valid argument not to treat too lightly with this particular case. But Joan took charge that time because a drawing like that doesn’t just appear out of nowhere. Resentment like that builds over time, and combined with what Coventry threw at Gregson, about the whole precinct feeling insulted by Sherlock and Joan’s involvement… not a good day for consulting detectives. So Joan is right, Sherlock should take some more care with their colleagues. He’s fully capable, we know that. As such Joan is working hard to subvert the trope of the Asshole Who Gets Away With Everything. As Sherlock tells her at the end of the episode that he is who he is, that he will not change, that he only makes an exceptional effort for her, and Joan replies that no-one can accept such an understanding forever, there is a little clock put on their partnership. It’s small, now. But what if it gets to grow? Joan is warning Sherlock. We’ll see how that plays out. It definitely shakes up the cozy little world they’ve ensconsed themselves in.

As we can see, Sherlock still does that thing where he thinks that, when going down the dark path is a good idea, he wants to leave Joan out of it. When Bundsch steps up his game and abducts another woman, letting Sherlock and Joan know about it, bold as brass, Sherlock sees no other option but to make sure that he will go down for this one — by framing him. Meretricious, and a Happy New Year.

Thank goodness, Joan can persuade him to actually use his brain rather than his desperation to think, and reminds him that Jenna has no chance of survival if they just take Bundsch into custody. So Sherlock finally figures out where the killer keeps his victims — close, and where no-one can hear them scream for help. In a twist utterly heartbreaking, they discover that one of the women who had been taken had been alive inside the sound-isolated walls of Bundsch’s studio for ages.

Next: Tremors.