Big changes are coming to "Castle" in its eighth season as shown in the show's first promo. Beckett celebrates her promotion as the new precinct captain and Castle gets a new crime-solving partner, namely his daughter Alexis.

"Everything you think you know is about to change," says the voice over.

Beckett (Stana Katic) admits in the new trailer that she's "exhilarated and frightened and everything in between" as she starts her new job. But her new position won't keep her husband Castle (Nathan Fillion) out of harm's way as the promo ends with one criminal threatening the crime novelist's life.

He may be wishing he were dead with a huge tarantula crawling over his face. Eek!

The first look also reveals college senior Alexis (Molly Quinn) has joined her Castle's private investigative service and is clearing cases faster than her sleuthing father.

"Step your game up," she challenges her dad after she solves four cases, more than he has solved.

The promo gives a first look at the team's newest addition, Hayley Shipton (Toks Olagundoye), who joins the squad as a free-spirited and quick-witted independent investigator. She may teach Alexis a few things about the investigative business as she takes Castle's only child under her wing in the new season.

Check out the full promo below and be sure to catch the eighth season premiere on Monday, Sept. 21 at 10 p.m. on ABC.