Watch Castle Online - Full Episodes

Castle is the critically acclaimed hit series from ABC, starring Nathan Fillion (Firefly, Buffy the Vampire Slayer) and Stana Katic (Quantum of Solace, The Morning After) as the funny, lovable writer-and-cop duo, Castle and Beckett.

Richard Castle is a renowned New York author who specializes in writing crime thrillers, boasting several bestsellers among his many novels. But when a serial killer starts killing people based on the murders in his books, he's called in to help the NYPD investigate the murders and try to predict the killer's next move. He's partnered with Kate Beckett, one of the 12th Precinct's best homicide detectives, and together they search for clues in a fast-paced race to catch the killer before he strikes again.

As they continue to work together, it becomes clear that these two are meant for each other. The back-and-forth banter is fun and engaging, and jokes are constant and hilarious. It's clear that their personalities compliment each other, Castle with his fun-loving playboy attitude, and Beckett with her crime solving smarts and witty retorts to his (admittedly corny) jokes.

They work well together, and Castle realizes this.

Using his connections to friends in high places (most notably the fictional Mayor of New York City), he secures a position at the 12th Precinct as Beckett's full-time (civilian) partner, under the guise of using her as a muse for his next set of novels. However, it's fairly obvious that he's mostly in it because he likes Beckett. She intrigues him in a way no other woman has before (he's been married and divorced twice already), and he wants to get to know her better. As established in the pilot episode, she tends to take "the weird cases", and she has a mysterious past that slowly unfolds over the course of the show.

The writers, Andrew Marlowe (Hollow Man, Air Force One) and Will Beall (Gangster Squad), do a brilliant job, and each episode has you trying to guess who the killer is.

In addition, the acting is phenomenal. The supporting cast does an incredible job of making the show feel realistic while still managing to be enjoyable and focus on character development (especially Seamus Dever & Jon Huertas as detectives Ryan and Esposito).Castle has currently aired for 4 consecutive seasons (as of summer 2012), and a fifth season has been confirmed by ABC.