After a very long and drawn-out process, ABC has officially decided to cancel Castle, Deadline reports.

The series had a shakeup not too long ago when the network announced on April 19 that Stana Katic would be exiting Castle after playing Detective Kate Beckett for 8 seasons. Katic and series regular Tamala Jones had not been invited back for a ninth season should Castle be renewed due to a budget cut.

The budget cut is the official reason. There is also speculation that off-camera tension between Nathan Fillion and Katic made it too difficult for the co-stars to work together, and Katic supposedly almost did not renew her contract for an eigth season.

Castle struggled in the ratings this year, but in the second half of the season the number began to climb. But it wasn’t enough.

Even though a ninth season had not been guaranteed, some of the cast members had already signed on for a ninth and final season. Nathan Fillion Seamus Dever signed contracts for another season of Castle and Jon Huertas was expected to sign on as well.

The decision not to renew Castle is very last minute for the show. The season 8 finale, which now also qualifies as the series finale, airs this Monday. Unfortunately for the fans, this probably means we won’t get a very satisfying ending to the series since the showrunners were hoping to squeeze out one last season.

However, the writers were prepared for the event that Castle might not last another season. showrunner Alexi Hawley told TVGuide.com “We are planning the finale to end in a cliff-hanger, but in a worst-case scenario, there’s an additional scene we won’t say much about that exists in case they tell us we’re not coming back.”

What Hawley described as the “worst-case scenario” is happening.

Series creator Andrew Marlowe addressed the cancellation via Twitter.

To the whole Castle family- our amazing cast, our remarkable crew, our imaginative writers & our wonderful fans, thank you for 8 amzing yrs!

— Andrew W. Marlowe (@AndrewWMarlowe) May 12, 2016

Thx 4 the shout out @RobHanning & thx 4 all the magic you brought to our #Castle. Helluva run, my friend. #NoRobots https://t.co/4b3KVHlSh1

— Andrew W. Marlowe (@AndrewWMarlowe) April 27, 2016

Marlowe served as showrunner for Castle from its premiere mid-season in 2009 until stepping down before season 7. From season 7 onward Alexi Hawley and Terence Paul Winter served as showrunners, but Marlowe has continued to stay close to the series.

The cancellation raises the question as to how the series will end. If ABC had renewed Castle for a ninth season, then they would have to explain Detective Kate Beckett’s absence. The promo for the upcoming finale hints at a potential tragic end for Beckett, which now would be a particularly cruel ending for the fans.

The (now) series finale of Castle will premiere this Monday on ABC.