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Castle - Episode 4.16 - Linchpin - Promotional Photos

CASTLE - "Linchpin" - In the explosive conclusion of a two-part story arc that began last week with "Pandora," 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, on "Castle," MONDAY, FEBRUARY 20 (10:01-11:00 p.m., ET), on the ABC Television Network. In the episode, Jennifer Beals ("The Chicago Code," "Flashdance") continues as Sophia Conrad - a smart, commanding and sexy CIA operative who was Castle's inspiration for Clara Strike in the Derrick Storm series of books -- and Josh Stamberg ("Drop Dead Diva") is back as intelligence officer Martin Danberg. (ABC/COLLEEN HAYES) JADE CARTER, NATHAN FILLION, JENNIFER BEALS, STANA KATIC

Larger ones later.