*Review contains spoilers, so read at your own risk!*
The amazing conclusion to 3XK was not a disappointment. Well, at least to me. It was out there and a bit dark, but like the Captain awesomely put it, Castle has to think outside the box in order to get each case done. It was that out of the box thinking that they needed in order to stop this killer once and for all.
Until the very end of the episode, I was thinking Castle had really gone out there. That he was acting out of revenge and hatred for the guy and trying, desperately, to get Kate back no matter what. Even if that meant he went above the law. But little did we know, it was all apart of the plan in order to get one step ahead of Jerry.
All this time, Castle was supposedly acting alone, but he wasn't. When he realized that they couldn't catch Jerry with a normal man hunt, that that would just be playing right into his game, Castle concocted this plan in his head and it all worked like clock work.
Castle telling Jerry all that was happening and having it dawn on him (Jerry) and killing him once and for all, was probably the best revenge Castle could have ever asked for. But Castle didn't do it. All Castle did was just sit there and fill Jerry in on what was happening while Espo outside was setting up the shot. The police force was in on it the whole time. Even though the Captain didn't sound like she totally was with the idea, but like she said, she knew that it was those crazy plans that Kate always talked about, that got the job done and it did.
The reunion was one of the best ones I've seen in a while. Though, I kind of wish Kate would have been a little more thrilled about seeing Castle, but I mean, she did just kill Kelly, so she probably was still getting over the shock. It'll take Kate some time to get over that whole situation, but with Castle's help, I'm sure she'll get through it.
I didn't know all of this led to Castle being reinstated with the police force! That was the best news anybody to give a fan. Sure, I loved the PI work and if Castle ever had to go back to it, I could enjoy it again, but now that he's back at home with everybody he loves and the job he loves, that's even better.