ABC has released a synopsis for the first episode of Castle season 8, and it's a doozy.

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The first episode of Castle season 8 is titled XY and now we know some details on what goes down in it. The synopsis is as follows:

"After passing the Captain's exam in the Season 7 finale, Beckett [Stana Katic] was surprised with an offer to run for State Senate," the synopsis reads. "In the action packed season premiere, Castle [Nathan Fillion] and Beckett are adjusting to Beckett's career change, when a call from a mysterious stranger sets off an explosive chain of events. There are two sides to every story, and this unique two-parter will explore the same story from each of their perspectives, first from Castle's side as he searches for Beckett in the exciting Season 8 premiere, 'XY.'"

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There will be a slew of guest stars in the premiere episode, including Sunkrish Bala as Vikram Singh, Brad Lee Wind as Franco Mancini, Coby Ryan McLaughlin as Brooks, Jack Coleman as Senator Will Bracken, Daisy Betts as A.J. Yes, that's right, Senator Bracken is back!

The second episode is titled XX, presumably centering on Beckett's perspective. It will be interesting to see how Beckett goes missing. Will Bracken's reemergence have anything to do with it? Only time will tell.

Castle season 8 premieres Monday, Sept. 21 at 10 p.m. ET/PT on ABC.

Tags: Castle television ABC