The fate of ABC's Castle may still be unknown, but there are rumors that the network may renew it for one final season.

ABC renewed 15 shows in March, including longtime favorites like Once Upon a Time, Grey's Anatomy and Dancing With the Stars, but curiously missing from that list was Castle. The procedural is currently in its eighth season and stars Nathan Fillion and Stana Katic are on one-year contracts at this point.

A new Deadline report states that Fillion is still in talks with producers for a new contract but "there are hopeful signs that the venerable series, now in Season 8, will get a final chapter."

It is unclear if the idea of a "final chapter" is speculation on Deadline's part or if that is an actual plan for ABC and the long-running series. Deadline also notes that this ninth and final season could have a shorter run than the usual 22-24 episodes.

Castle co-showrunner Alexi Hawley previously spoke about the possibility of going further with the show, even with lead characters Castle and/or Beckett gone.

"If we had our choice, it would be the same cast, it would be the same show," Hawley assured. "We've done some fun stuff this year so that it has a little different energy that could absolutely carry through to a Season 9. But both of us are very invested in this, and we understand that Castle has always been about Beckett and Castle. So the idea of that not happening is daunting, and we're rooting against that."

There's also a new TVLine report that the series possibly filmed two different endings to season 8. One ending would be a normal season finale, while the other would be a series finale - which would probably have a much more satisfying conclusion.

Castle airs Mondays at 10 p.m. ET/PT on ABC.

Tags: Castle television ABC