Previously on Elementary: Dead Clade Walking.

The — aside from the wonderfully unperturbed handling of gender-flexible sexual and/or relationships — relatively uninspired case of a dead ballerina was accompanied by a better look at Joan’s life, values, and motivations; as well as a heartwarming example of the depth of her connection with Sherlock.

The revelation that Joan’s birth father was diagnosed with schizophrenia shortly after she was born, that he lives on the street, and that they sometimes see each other and he recognises her depending on whether he’s taking his meds came completely out of the blue. That means it’s a well-kept and guarded secret — Sherlock googled her, remember? That he didn’t find out means that he never did more than the initial digging. Finding someone as off the grid as Joan’s dad is difficult, but not impossible, not for someone like Sherlock. He could have procured her birth certificate, could have finagled information out of anyone — but he didn’t. He researched enough to know more about her immediate background, such as the rumours of her stepfather having an affair, mostly to needle her, but that’s it. He respected those boundaries, and not just because they were growing closer. There was a relatively long stretch of time when Sherlock was  still counting the days until when Joan would leave the Brownstone. Still, he didn’t pry into her life beyond what went on on-screen — like when he tried to convince her to return to actively practising medicine.

So, what we have here is not only a vital piece of Joan’s life, a huge and unmistakable marker of how compassionate, driven, and principled she is, but also an admission: “It shouldn’t be a secret. Especially not from you.”

It’s not something she was keeping from Sherlock for a specific reason… but it is tough to talk about, and it isn’t really something that would come up naturally. And yet, although Sherlock could have pried the answer to the question of why she’s so active in charity work and suchlike out of her much earlier, it only happens now. When he’s reasonably sure that she will want to answer him, and when it doesn’t mean any awkwardness between them. There isn’t really anything Sherlock can say to help — he knows Joan doesn’t need his pity, nor any platitudes about how that must be hard. But he knows what he can do: donate blankets. He joins Joan in this effort to help, if not her father directly, but the people with similar problems. Donating blankets on a cold night is a simple kindness, but one that goes a long way. By doing this, he tells Joan that he cares about her, about her father. It’s an open admission of compassion and decency that Sherlock doesn’t often show so freely and guilelessly.

Many of these gestures between Joan and Sherlock happen with a certain weight, some sort of gravitas, but it never gets too much, and it never has too much attention drawn to it. They’re very carefully drawing, brushing away, and redrawing lines in the sand while negotiating their relationship and the influence they have on one another.

Next: The One Percent Solution.