So, there were two main plots going on in this episode. One of them was pretty neutral for me. Nothing bad, nothing amazing. The other one was freakin' awesome. I'll start with the lukewarm stuff and move on to what I really loved.
Sherlock is bored, and decides to go try and find a case by looking for unsolved mysteries in corpses. This I liked. It was a funny setup. Rather than a case dropping into their laps, they really had to seek it out. The case itself was a bit of a mess in my opinion. Basically, it all had to do with the Russian mafia. There were multiple twists and the criminal in the end was one of the original participants: the wife of the body that Sherlock saw in the morgue.
There were some decent bits here and there. I liked the way that Sherlock and Joan tracked down part of the mafia by finding a beauty salon and identifying it as a front. The guest actors were pretty compelling, actually. Things I didn't like? I really want more Gregson and Bell. I think I mentioned that for last week's review, too. I just really want to see more of these two, and I feel a bit robbed when they play such a background role. Last season, they had so much more to do in terms of advancing the plot. I'd love to see them interact with our two leads a bit more.
And speaking of our two leads, let's take a look at the other plot. Joan goes to meet her friend Jen who tells her about an amazing one night stand she had had some time ago with a man named Tony. Jen asks for Joan's help tracking this man down, and because of the lack of a real case, Joan decides to investigate. Sherlock thinks it's a total waste of time, but Joan actually gets pretty far in her investigation. When she finds footage that she thinks might contain the mystery man, Sherlock reveals the truth: it was him!
Joan is understandably confused and furious when she finds out that Sherlock had a one night stand with her friend. It gets even worse when he reveals the reason he hooked up with her was to gather information about Joan... this was back shortly after they met, and Sherlock had been following her. He apologizes, and even goes to explain the whole thing to Jen... with the result that the two of them have sex again. Watson is again unhappy when she finds out.
I liked this plot because it really showed how much Sherlock has grown. He used to be okay with sleeping around to get information, but now he's a more honest guy. He actually does tell Jen the truth, even though he does sleep with her again. I just really enjoyed the growing trust between our two main characters. I also liked the Jen character. She wasn't a lovesick idiot, she wasn't a totally ditsy little girl. She was infatuated with a guy, and then she found out the truth about him and decided to move on. But Jen and Sherlock obviously had chemistry, and neither one of them is shamed at all by the narrative because they have sex. I just found all of that very refreshing.
Anyway, the crime part of this episode was nothing special. If anything, it was a bit confusing and clunky. But the B plot with Joan and Jen was really funny, and I was giggling through a lot of those scenes.