A major challenge in Booth (David Boreanaz) and Brennan's (Emily Deschanel) marriage will unfold in the 12th and final season of "Bones" on FOX.

At the end of season 11, Brennan was abducted by her former intern, Zack (Eric Millegan). He appeared to have escaped the psychiatric hospital, where he was detained, to torment his former mentor.

Brennan and Zack had a close working relationship in the past, and she had a hard time accepting the fact that her brilliant intern will do something terrible to her. According to speculations on the upcoming season, Brennan could escape Zack's clutches. But their troubles will not go away since the couple will have arguments regarding Zack's possible fate.

Meanwhile, new details about the plot of "Bones" season 12 have been revealed by TVLine's Ask Ausiello. According to the report, veteran actors Ed Asner and Hal Holbrook will guest-star in the third episode, and they will be joined by another seasoned star, June Squibb.

Asner will reportedly portray the role of a kindly man named Mike Mancuso, who is actually a deceptive and two-faced man in disguise. Holbrook, on the other hand, will portray the role of a Marine Corp veteran named Red Fletcher, who seems to be an older version of Agent Booth. Squibb will portay the role of a retirement home resident in the said episode.

Another report from the same publication revealed that Cam (Tamara Taylor) and Arastoo's (Pej Vahdat) upcoming wedding will not be as grand as Brennan and Booth's.

"I think [we had our] big wedding with Brennan and Booth," co-showrunner Jonathan Collier said. "So let's just say that it's going to be exciting and different."

FOX has yet to announce the official premiere date of "Bones" season 12, but the series is expected to premiere sometime in 2017.