'Castle' Season 8 Spoilers: New Promo Photo Teases Daughter Alexis Joining Rick's Private Investigator Firm [VIDEO]

Molly Quinn, pictured at Entertainment Weekly's Comic-Con 2015 party at the Hard Rock Hotel on July 11, 2015 in San Diego, California, will have a larger role to play as Alexis Castle in "Castle" Season 8. Jason Merritt/Getty Images

In the Season 8 premiere of “Castle” writer Rick Castle (Nathan Fillion) will be starting a new job as a private investigator, and trying to track down his wife, Kate Beckett (Stana Katic), after she goes missing. That will be a lot to handle and its tough times like these when family is most important. Luckily, Castle’s daughter, Alexis (Molly C. Quinn), will have her father’s back.

A promo photo for the new episodes, released Wednesday on Twitter, reveals that Alexis will be joining her dad’s new private eye firm and helping him solve cases. With Castle on the outs with the police and his wife busy accepting a promotion to Captain, it seems the perfect time for Castle to gain a new partner, and perhaps his daughter is the perfect fit. Their first case will be finding a missing Beckett.

See the promo photo in the tweet below:

Solving crime runs in the family. A new season of #Castle premieres Monday, September 21 at 10|9c on ABC. pic.twitter.com/wPqQnOyrIW
— Castle (@Castle_ABC) September 9, 2015

The synopsis for the premiere episode reveals that Beckett will disappear not long after Castle gets a mysterious phone call. It will be up to the writer to save his new bride.

Alexis will not just be helping her father. She will also develop a bond with newcomer Hayley (Toks Olagundoye), a security specialist who joins the precinct and becomes an invaluable asset for Castle in his new private eye venture. “Castle” showrunner Alexi Hawley told Entertainment Weekly that Alexis will come to look up to Hayley.

"We like the idea of [Hayley] as a mentor to Alexis in a way that Beckett has been, but because she's also Castle's wife, ultimately Hayley can play a little bit more of an older sister," said Hawley. "This season is really about growing [actress Molly C. Quinn] up. She's been playing the child for seven seasons and now she's 21 years old. She's a grown up. This year, she's going to be more sophisticated. That relationship with her father will change because she's not a little girl anymore."

Watch the promo for “Castle” Season 8 below: