Castle S4E16 Linchpin (2)

Castle Season 4 Episode 16 Online – Castle & Beckett race to find the "Linchpin" in order to stop the first domino in a chain of events which will plunge the United States into war. Their efforts continue to put Castle in contact with Sophia Turner - a smart, commanding and sexy CIA operative who was Castle's inspiration for Clara Strike in the "Derrick Storm" series of books; and intelligence officer Martin Danberg is back.