Castle (2009)
S04E16 Linchpin (2)
Episode Overview
Castle and Beckett are on a frantic mission to locate the "Linchpin" to prevent the initial trigger that could lead the United States into war. As they delve deeper into the investigation, Castle encounters Sophia Conrad, a savvy and alluring CIA agent who inspired the character Clara Strike in his "Derrick Storm" novels. Additionally, the intelligence officer Martin Danberg makes a return, adding another layer of complexity to their high-stakes pursuit.