Hayley quickly proved her worth in helping Castle track down Beckett in the two-part premiere. The newly minted captain gets a first-hand look at Hayley's investigative skills when they partner up in episode five.

Despite her series regular status, Toks Olagundoye sits out the next couple episodes as "Castle" shifts the focus to Castle (Nathan Fillion) and Beckett's (Stana Katic) deteriorating marriage. But she'll return from her trip out west to mix things up with the team again.

"When she comes back, she's actually working with Beckett," co-showrunner Alexi Hawley told TVLine. "She's sort of like a force of nature who comes in and bounces off of our characters with an interesting point of view."

Episode five, titled "The Nose," will find Castle and Beckett trying to track down the mastermind of a million-dollar heist. The episode also features guest star Stephnie Weir who will play Mia Lazlo, a real character who begrudgingly helps Castle and Beckett with the investigation, according to TVLine.

No word on whether Beckett will enlist Hayley's services to uncover Bracken's (Jack Coleman) partner a.k.a. LOCKSAT, but she's already got her friend Vikram (Sunkrish Bala) on the case in next week's episode.

"Ultimately he is tied to Beckett's obsession, her search [for Bracken's partner aka LOCKSAT]," Hawley said. "We bring him into the precinct to work as a sort of digital investigator for them. He's working at the 12th, but he's mainly there to help Beckett go down her road."

Beckett is determined to find the real culprit behind the murder of her former team at the Attorney General's office and who set up the now deceased Assistant AG Allison Hyde as the fall guy. To carry out her investigation, she walked out on her marriage with Castle to keep him out of harm's way.

This isn't the end of Caskett, though. An upcoming episode titled "Mr. and Mrs. Castle" will clue fans in to what the "Castle" bosses have in mind for the couple.

"For the fans who right now are going, 'What the heck and Terence and Alexi doing?!,' when they see that episode they'll understand and see what we're going for," co-showrunner Terence Paul Winter told TVLine.

"Castle" airs on Mondays at 10 p.m. on ABC.