On the series last season, Castle (Nathan Fillion) and Beckett's (Stana Katic) relationship grew stronger as they dodged bullets, captured killers and solved countless murder cases in their unorthodox partnership.
But by the Season 2 finale, Beckett's new relationship with a Robbery detective had pushed Castle away, forcing them both to confront their feelings.
When Castle left to finish writing his second Nikki Heat novel, "Naked Heat," Beckett had to watch him walk away, unable to express her true feelings and unsure whether he would return to the precinct.
When the new season of Castle begins, Beckett hasn't heard from Castle since he left for the Hamptons months ago to finish writing his second Nikki Heat novel, "Naked Heat". The most Beckett, Ryan and Esposito have seen of Castle is a bookstore standee of him advertising an upcoming book signing.
So when Beckett and her team burst into a shadowy apartment on the trail of a murderer, the last thing they expect to see is the real-life Castle standing over a dead woman's body holding a gun!
As Castle protests his innocence, Beckett has no choice but to arrest him on suspicion of murder.
The series stars Nathan Fillion as Richard Castle, Stana Katic as Detective Kate Beckett, Ruben Santiago-Hudson as NYPD Captain Roy Montgomery, Tamala Jones as Medical Examiner Lanie Parish, Jon Huertas as NYPD Detective Javier Esposito, Seamus Dever as NYPD Detective Kevin Ryan, Molly Quinn as Alexis Castle, with Susan Sullivan as Martha Rodgers.
Castle is produced by ABC Studios. Andrew Marlowe is creator/executive producer, with Rob Bowman, Laurie Zaks and David Amann also executive producers.