New girl Hayley Shipton may not cause problems for Beckett and Castle, but her role as a mentor for Alexis could be tough for Castle to swallow as he watches his little girl become a grown woman.
Toks Olagundoye will join "Castle" this season as the free-spirited and quick-witted independent investigator who will assist on cases with the mystery writer [Nathan Fillion] and the NYPD. She also will act as an "older sister" for Alexis (Molly Quinn) who goes through a more adult makeover in season eight.
"We like the idea of her as a mentor to Alexis in a way that Beckett [Stana Katic] has been, but because she's also Castle's wife, ultimately Hayley can play a little bit more of an older sister," co-showrunner Alexi Hawley told Entertainment Weekly.
Alexis' makeover includes a more mature haircut and possibly her first sexual relationship with a new boyfriend.
"This season is really about growing Molly 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," Hawley said.
Hayley will add a new energy to the 12th precinct and a new partner for Castle to work with while Beckett's transitions into the captain's chair. While she's not as a rule-averse as Det. Ethan Slaughter (played by Adam Baldwin, who also returns this season), Hayley likes to have fun and isn't opposed to breaking and entering instead of obtaining a warrant.
"She's a little easier than Adam Baldwin [was] on him, but there's definitely an energy about her which is a lot of fun," Hawley said.
Castle can still find some stability in his life with his mother Martha, who did move out of his loft last season but remains ever present in his life.
"She's very much a part of Castle's life. Don't think that just because she now has her own place and is doing well on Broadway that we're not going to see her sharing her wisdom with her favorite and only son," co-showrunner Terence Paul Winter told TVLine.
Not so present is Castle's father, who last appeared in season six. His return is still unknown but he will get mentioned in the season premiere, according to TVLine.
"Castle" returns on Monday, Sept. 21 at 10 p.m. on ABC.
