I really, really enjoyed this episode. And yet, I feel like it went wrong somewhere.
It was just too...neat.
For about the first half, I was deep into the storyline. There were an exceptional number of twists and turns in this one, I felt - the writers of Castle are masters of red herring, to be sure. The case kept getting bigger and more intricate as the episode wore on, and always in an acceptably believable way. There's a mastery to that type of storytelling. The fact that I was able to call one of the major twists is maybe a sign that they were just a bit too obvious, but I was only partially correct so even that worked out fine.
Michael Trucco as Detective Tom Demming proved to be a great addition to Castle. He'll be around until the end of the season, and I'm actually alright with that. He and Stana Katic - and he and Nathan Fillion, to an extent - have pretty solid chemistry. Nowhere near as phenomenal as the chemistry between the two stars and the supporting cast, but he fits in. Also, he wears a purple tie and spends a good portion of the episode in workout gear and sweat, which is a good look for him. The sparring sessions with innuendo were not particularly original, but fun to watch and the fight choreography was quite creative.
Two elements involving Demming especially stood out to me as excellent. First, the love triangle bit. This is always a tricky place to go on a show where the not-quite-romantic-involvement of the two main characters is pivotal. Leave it to Castle, though, to get it right. Beckett and Demming have chemistry, if not an overly large amount, and he's likeable enough that I don't dismiss him out of hand via the You Aren't Castle criterium. And, he provides an opportunity to show that Castle and Beckett aren't whiners, they aren't mooners, and they aren't overtly/irritatingly jealous. Wishful and attracted, certainly, but in no way aggravatingly obvious. It's a nice change from the norm, e.g. Booth and Brennan of Bones. Last note on this element: Michael Trucco must be tired of playing the likeable-but-not-enough third wheel (see: his character in BSG).
Probably the best thing about the entrance of Demming, though, is that he had a function beyond the above. He provided the opening for a more in-depth look at Esposito. The second-tier characters of Castle get kind of shafted. They provide so much of the comedy but have so little real development as human beings. "Den of Thieves" really delved into Javier Esposito, though. He's always had a personality, to be sure, but I feel like I understand it a lot more now, and therefore have an elevated sense of respect for him as something beyond comic relief. Ryan too, by default.
Despite all that good stuff, my overall feeling regarding "Den of Thieves" is nearing disappointment. The story seemed to start falling apart toward the end of the episode. Well, maybe "falling apart" isn't the right phrase. More like...all the elements just fell into place way too neatly. If there's such a thing as incredibly underwhelming, this was it. No real twists, nothing really unexpected-and-out-of-the-blue-but-totally-awesome. Just, "Oh. It was the dickish IA guy. My goodness." Nothing against Scott Cohen, who was plenty scary in that final showdown, but Holliwell as the bad guy was just such an obvious mood. After the driving experience of the body of the episode, the conclusion was a bit of a let down.
As I said, Demming'll be around for a couple more episodes. I'm hoping that Michael Ironside's character, crimelord-type Victor Racine, will also stick around as an adversary to lend some cohesion to the end of the season.
But maybe not. As long as the show picks back up from this week, I don't particularly care how.
(This review also posted on my blog at http://meltedbrain.wordpress.com.)