Castle is officially on a month-long hiatus and will return to ABC on March 8.  Instead of mourning Monday nights without one of the funniest duos on TV, though, fans can get excited over an upcoming storyline.

As previously noted, Dana Delany will appear on two episodes of the dramedy this March. She'll play a FBI agent that joins Castle and Beckett in the search for a serial killer that's obsessed with Nikki Heat.

Castle is about a famous mystery novelist played by Nathan Fillion as Richard Castle, who is initially called in to help the NYPD solve a copy-cat murder based on his novels.  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 Javier Esposito, Kevin Ryan and Captain Roy Montgomery. They also work with medical examiner Lanie Parish. Richard's family includes his mother Martha Rodgers, who was a broadway diva and his daughter.

Heat Wave, the novel the fictional Richard Castle wrote in the series, is published by Hyperion. Ghost-written under the name "Richard Castle", it is entirely in character from the dedication to the acknowledgments, although the latter references the principal cast and the show's creators by name. The first half of the novel was released on the ABC website in weekly increments, but it must be purchased to be read in its entirety. Heat Wave was released on September 29, 2009, and debuted at #26 on the New York Times Best Seller list. In its 4th week on the list, Heat Wave broke into the top 10 at #6.

On May 15, 2009, Variety reported that ABC had renewed Castle for a second season. The second season premiered on Monday, September 21, 2009. On October 20, reports emerged that ABC has ordered a full season of 22 episodes.