First off, the traffic here on the Castle forums has really, really, really died down...
Another exciting start to a Castle two-parter. Love Alexis' new internship, hope they keep that up for a while.
I'm kinda of hoping for a twist being that the CIA group that Beckett and Castle are reporting to turns out to be rogue and was the "think tank" that the female mathematician was consulting for and the rogue agent actually is trying to stop them. From the previews for the second part, though, that's not happening.
Nice cliffhanger ending.