Wow, that was pretty intense, wasn't it? "Setup" is a setup episode, laying out the scenario of a dirty bomb and putting out the suspects, before narrowing it down towards the end. Apparently, the dirty bomb isn't in the hands of Muslim terrorists, as they are ruled out (again, Castle's wild imagination is correct).
The strength of the episode lies not in the plot, but in Beckett whose boyfriend is leaving once again. While under quarantine with Castle, she states what she wants, someone reliable and will always be there. Of course, that's Castle, but before anything else can happen, they're cleared. The episode ends with Castle and Beckett off the case officially, but working on the case together--and they're trapped in a freezer.
Score: 8.9/10
