KATE BECKETT: THE DETECTIVE

Beckett is a detective with the Twelfth Precinct Homicide Squad of the New York City Police Department, where she worked with fellow detectives Javier Esposito and Kevin Ryan and medical examiner Lanie Parish under Captain Roy Montgomery until he was killed at the end of season 3. In season 4, Montgomery is replaced by Victoria "Iron" Gates. In the pilot episode, Beckett leads the investigation into the murder of Allison Tisdale, which is staged in the style of a death scene described in the Richard Castle novel Flowers For Your Grave, along with other murders based on Castle's fiction.

Beckett is forced to have Castle consult on the case, and though she tries to contain his access, he repeatedly violates police protocol. Although the killer is apparently caught when he leaves his fingerprints on a note he allegedly sent to Castle, Castle convinces Beckett to continue the investigation based on a hunch, the two discovering that the killer was actually Allison's brother, setting up a mentally ill client of his sister—a social worker—so that he could claim the majority of their father's estate due to his father suffering from terminal cancer. By the end of the pilot, Castle uses his friendship with the Mayor to get partnered with Beckett under the pretense of conducting research for a new series of novels starring a detective based on Beckett. Toward the end of the fourth episode, Beckett's literary alter-ego is revealed to be named "Nikki Heat," much to Beckett's annoyance.

RICHARD CASTLE: THE WRITTER

Richard Castle is the father of Alexis Castle and the son of Martha Rodgers (who lives with him). Castle's birth name is Richard Alexander Rodgers, but he changed it to Richard Edgar Castle when he became a writer (Edgar in honor of Edgar Allan Poe). Fillion describes the family dynamic as unconventional because Castle is "mothered by his... daughter, [then]... turns around and mothers his own mother". As a child, he never knew who his father was—reasoning that he never missed having a father as he never had anything to miss, and it allowed him to imagine that his father could be anyone he wished—and was looked after by a nanny who spent most of her time watching daytime television, with One Life to Live as the inspiration to write his first novel. He also claims to have been kicked out of all of New York's finer academic institutions at least once, and to have picked up speed reading while spending his days as a child in the New York Public Library.

Castle has been married and divorced twice. His first wife was Alexis' mother, Meredith, an impulsive, free-spirited actress. She and Richard occasionally meet for a sexual liaison, causing Richard to refer to her metaphorically as a "deep-fried twinkie" (something that is a treat on occasion, but to have it every day would kill you) when she contemplated moving back to New York. His second wife was Gina Cowell, his publisher, a role she continues after their divorce. Castle and Gina became involved again, briefly, when she spent a summer with him in the Hamptons supervising his second Nikki Heat novel, but they soon ended their relationship.

Castle has sole custody of his daughter, Alexis. As a result of his own experiences being raised by a nanny, he insisted on raising her himself, made easier by the fact that he works from his large loft apartment. Alexis is quite mature and responsible compared to her father and in some sense parents him and herself. Richard takes great care to look after her well-being, but also behaves like a surrogate sibling in some ways.

CASTLE: THE BEGINNING

RICHARD CASTLE, THE WRITER & KATE BECKETT, THE DETECTIVE

Castle is an American comedy-drama television series, which premiered on ABC on March 9, 2009. The series is produced jointly by Beacon Pictures and ABC Studios. Created by Andrew W. Marlowe it primarily traces the lives of Richard Castle, a best-selling mystery novelist, and NYPD Detective Kate Beckett as they solve various unusual crimes in New York City. Detective Beckett is initially infuriated at the thought of working with a writer and goes to great lengths to keep him out of her way. However, the two soon start developing feelings for each other. The show focuses on the romantic tension between the two lead characters, and also on the unsolved homicide of Beckett's mother.

Season four premiered on September 19, 2011. On January 12, 2012 the series won two awards at the People's Choice Awards, including Favorite TV Crime Drama and Favorite TV Drama Actor (Nathan Fillion). The show has also won three awards in TV Guide Magazine's Fan Favorite Awards, including Favorite Drama Series and also Award for Favorite Couple two years in a row. The show has had a gradual increase in ratings and its pilot episode was watched by an estimated 10.76 million viewers. On May 10, 2012, Castle was renewed for a fifth season by ABC, which started on Monday September 24, 2012. An additional episode was ordered on October 19, 2012 to bring season five up to 23 episodes.