"Castle" Season 8 episodes will definitely get more intense after the shocking departure of Penny Johnson Jerald's character, Captain Victoria Gates. And as unexpected changes and twists shake things up in the lives of crime-busting couple Richard Castle (Nathan Fillion) and Kate Beckett (Stana Katic), more conflicts will surely arise.

Since "Castle" Season 8 premiere is just around the corner, its two-hour episode will delve deeper into Rick's investigation over his father's disappearance, Design & Trend noted. The investigation will also remind him of his own vanishing in the past.

Aside from Rick's dad, fans are also wondering if Rick's mom, Martha (Susan Sullivan), will return in "Castle" Season 8, co-showrunner Terence Paul Winter said that she will be part of Castle's life.

"She's very much a part of Castle's life," Winter told TVLine. "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."

New co-showrunner Alexi Hawley also added that they'll be shaking things up in the upcoming season.

"The show has been doing a great job with what it's been doing, but now we've been given an opportunity to really sort of add some energy to it," Hawley said.

Meanwhile, "Castle" Season 8 will also introduce a new investigator. According to Entertainment Weekly, "Neighbors" star Toks Olagundoye will join the upcoming "Castle" cast as the free-spirited and quick-witted investigator Hayley Shipton. As said by Hawley, Shipton is a dynamic and fun character that the show doesn't have. And though she doesn't follow rules, she's a little easier than Detective Ethan Slaughter (Adam Baldwin), who will also return this season.

Moreover, Shipton will also serve another purpose in "Castle" Season 8 aside from working with Castle more after Beckett's promotion as the new captain.

"We like the idea of her as a mentor to Alexis (Molly C. Quinn) 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," Hawley said.

"This season is really about growing Molly up," she added. "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."

In "Castle" Season 8, Rick seems to be contemplating about a big change in his career. As per Fashion & Style, he will become a full-time investigator. Beckett, on the other hand, has chosen to stay in law enforcement.

"Castle" Season 8 is set to premiere on Sept. 21 at 10 p.m. on ABC.