The excitement brought about by "Castle" season 8 has not died down, yet another rumor has surfaced.

The latest rumor suggests that Nathan Fillion and Stana Kanic, who play the show's main characters Richard Castle and Kate Beckett, respectively, might not be returning to the show for another season. Thus, there is a possibility that their characters would be removed from the TV series' story line. 

Fillion and Kanic said, according to reports, that they haven't renewed their contracts yet. According to Fillion, he and co-star Kanic renewed their contract last year for one more season. Now, season 8 has yet to end, but no other official news with regard to its renewal has been released yet.

Rumors say that the ABC series hasn't generated enough viewers this season, so there are questions on whether or not it will have one more season. Despite these rumors, Movie News Guide reports that an interview with then ABC chairman Paul Lee said that they will keep the series moving even if the two lead stars leave and pursue other projects.

He further said at a Television Critics Association (TCA) panel in January that they would love to continue "Castle" because they already have a lot of ideas for the upcoming shows, reports Deadline Hollywood.

Other rumors say that ABC might have a spin-off show to keep the series from getting stale.

"Castle" is the story of a famous mystery writer who works with the New York police to solve crimes. The initial episode featured Castle looking for inspiration when a series of copycat crimes followed what he had written in his novels. 

Some of the major characters in the story include Seamus Dever (Kevin Ray), John Huertas (Javier Esposito), Susan Sullivan (Martha Rodgers), and Molly Quinn (Alexis Castle.

The television show was created by Andrew Marlowe. "Castle" season 8 airs Mondays at 10 p.m. EST on ABC.