The new promo for season 8 of ABC's Castle has been revealed, centering on Castle (Nathan Fillion) and Beckett's (Stana Katic) relationship.

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The promo, titled "Castle Is Back", features Castle and Beckett celebrating the latter's new promotion to precinct captain. She even has a sparkling cake with "Congratulations Captain Beckett" clearly visible.

The trailer also features an intriguing set of scenes that include a bloody bracelet that says "Always", a tarantula crawling on Castle's face and Beckett kicking some butt. During the tarantula crawling scene, Castle's life is threatened as he is asked to reveal where his wife is.

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Also, we see our first glimpse of Hayley (Toks Olagundoye), the new security specialist at the precinct. She is shown winking and smirking.

For those wondering about Hayley's addition to the force, new co-showrunner Alexi Hawley spoke with Entertainment Weekly about the dynamic she would bring.

"[Toks] plays a really dynamic, fun character," Hawley said. "It's a voice that the show doesn't have. What's great about her is Castle [Nathan Fillion] has been investigating cases police-adjacent, so it's always about doing things the way police would. She doesn't do things that way, so that fun dynamic of, 'No, we break in rather than get a warrant,' is kind of fun."

Fans don't have to worry about Hayley disrupting Castle and Beckett's loving marriage, however, as the showrunner insisted the show will always be about Caskett.

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