"Castle" Season 6 went on a monthlong hiatus but reports indicate ABC is airing a new Castle episode on April 21. ABC has yet to release an official statement about Castle Season 7, but Caskett fans remain optimistic. Stana Katic, meanwhile, takes a break on Twitter after releasing a Season 6 finale teaser.

Spoiler alert: This feature contains spoilers on Castle Season 6. Watch the Episode 20 promo here.

Castle series creator Andrew Marlowe does not want to confirm or deny whether 3XK or Senator Bracken (or both) will show up again in the Castle Season 6 finale. But Stana Katic seems to have hinted at least one person dies in the finale, which airs on ABC in a month's time.

"S6 finale had us saying goodbye to a number of colleagues today," Stana said on Twitter. On the one hand, she could mean that filming is over and it is time to say goodbye until Castle Season 7 starts filming. On the other, she could mean that one or more character dies in the Season 6 finale.

If there is death in the Castle Season 6 finale, then someone dangerous is attacking Rick Castle (Nathan Fillion), Beckett (Stana Katic), or the NYPD. "Will 3XK [aka Jerry Tyson] come back into play before the end of the season?" Givememyremote.com asked Marlowe. The showrunner quipped he thought 3XK (Michael Mosley) was dead, but his girlfriend could be alive.

Another dangerous enemy in the series is Senator William Bracken (Jack Coleman). The last time he appeared on the series, Beckett suffered torture. Marlowe had said Caskett fans will see more about the aftermath of this episode before the Season 6 finale.

"This story and what's gone on is something we plan to revisit before the end of the season," Marlowe told Givememyremote. While Castle Season 7 is technically non-existent yet, Caskett fans are hoping there will be more of extra-tough Beckett scenes in relation to Sen Bracken, aka Lazarus.

As for the Castle and Beckett wedding, Marlowe said there will be more "wedding conversations" for the rest of the Castle 6 episodes. Caskett fans are left to speculate on what is going to happen. But if there is death in the Castle Season 6 finale, this wedding is not likely to be a traditional solemn occasion, as in Booth's and Brennan's (David Boreanaz and Emily Deschanel, respectively) wedding in FOX's "Bones" Season 9.

WATCH: Castle Season 6, Episode 20 ("That 70s Show") | Apr. 21 New Episode | ABC Promo on YouTube

Castle Season 6 airs Mondays on ABC. The next new episode, "Law & Boarder," airs on Apr. 28.

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