ABC has released the official synopsis for the February 20th episode of Castle, "Linchpin". In this dynamic conclusion to "Pandora", Castle and Beckett are on a serious time table. Jennifer Beals and Josh Stamberg will be guest starring.

• 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.