So John Noble's name appears in the opening credits, which pretty much gives the game away, and we spend most of the episode waiting for Mr. Holmes to appear. Of course he doesn't until the very end, and I can't say I like Noble for the role, but we'll see.
Everything leading up to that moment is holdover from last season. Remember how Holmes was duped by Oscar and nearly beat him to death then did that heroin? Now the DA is deciding whether to charge Holmes, and neither Holmes nor Watson can get a job consulting for any major agencies. Looks like they'll be back to the old, "Find my cat" and, "Follow my husband, tell me what he's up to" cases.
But then a case does fall in their laps: Bloom, also from last season's finale, approaches Holmes and tells him (a) he did [accidentally] kill a couple addicts he had brought home for rough sex, including where they're buried, and (b) he didn't kill his wife. With that, Bloom kills himself, leaving Holmes to sort out whether finding Bloom's missing wife is worth his time. Well, but what else has he got to do while waiting on the DA's decision?
The case ends up being a somewhat interesting one, but I won't bother with the details. What's nice about this episode is the balance of story to character arc development. The actual mystery is punctuated by Holmes and Watson each doing their best to hold things together. Holmes tries to get the NYPD to at least keep Watson as a consultant; Watson, meanwhile, confronts Mr. Holmes' lackey to complain that Mr. Holmes keeps saying he's going to turn up but never does. The short story there: Don't make promises—or threats—you don't intend to keep.
I do have one beef with it all, though. Watson tells Holmes she doesn't want to do the job unless she's working with him. "I got into this to work with you," she says, more or less. But all last season had been about how she wanted to do her own thing, and how they'd have their own cases, etc. So WTF is this utter flip in character? Yes, we all prefer Holmes and Watson as a team. And I suppose at a stretch one might conjecture she's saying this because she wants to keep an eye on Holmes post-relapse? But that subtext wasn't there, and so her protest felt wrong.
Of course the mystery gets solved, and Holmes also gets a pass from the DA (which one may suspect came from dear old Daddy). And then we get the moment of Holmes confronting his father on the roof of the brownstone. And I don't know, but it fell flat for me. It had all the repression but none of the tension.
Anyway, it seems Holmes Sr. will be around for the time being. This could be an interesting avenue to explore, but they're going to have to do it just right. For me, it's not off to a promising start.
What I'd really like is a spinoff in which Mycroft and Lestrade solve mysteries together in South America while Mycroft tries to remain incognito. Because that would be awesome.