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.
Season 4 Episode 16 of Castle resulted in a 0.00 rating in the 18-49 demographic.
Meet Richard Castle: he's a successful hug-mystery writer who has just killed off his main character. However, it seems one of his fans liked his books just a bit too much when a copycat murderer starts running around killing people as described in Castle's books.
After being questioned by the police Richard joins forces with Detective Kate Beckett to solve this case. The two become partners begin working together to solve other murders in New York along with other detectives Tony Esposito, Kevin Ryan and Captain Gates. They also work with medical examiner Lanie Parish. Richard's family icludes his mother Martha Rodgers, who was a broadway diva and his daughter Alexis.