I posted yesterday the review for last season's White Collar, and I noted that it took them four episodes to get things back to normal in the series (cleaning up cliffhangers and corners the writers had painted themselves into). It took Castle four episodes to do the same thing.
I really enjoyed the episode a lot, and I'm glad things will be back to normal. Wonder if Sully will stick around for comic relief in the squad room? Looks like Pi is going to hang around for a bit.