'Bones' season 12 spoilers: Brennan's protégé, ex return

Two men in Brennan's (Emily Deschanel) life will be back to bother her when "Bones" returns for the 12th and final season in early January.

As soon as the premiere episode airs Tuesday, Jan. 3, fans will see the return of Brennan's former apprentice Zack Addy (Eric Millegan) who abducted her toward the end of season 11.

Based on one of the sneak peek for episode 1 titled "The Hope in the Horror," Zack will tell his former mentor that they have a lot of things to talk about. At first, Brennan will try to understand where Zack is coming from, but when he refused to let her go, she will tell him that her husband Booth (David Boreanaz) will come looking for her. Yet Zack will not allow Brennan to tell him what to do, and he will tell him that he be the one in charge this time.

In an interview with Oregon Live, Millegan revealed that fans of the series will learn the exact reason why his character decided to kidnap Brennan. "People won't be angry," he stated. "They won't be upset. They'll be very satisfied."

Meanwhile, executive producer Michael Peterson told TVLine that Brennan's ex, Tim "Sully" Sullivan, will also make an appearance in the final season of "Bones." According to Peterson, Sully will come just when Brennan and Booth are having a vulnerable period in their lives. "He comes back at a time in Brennan's life when she is emotionally unbalanced," the executive producer stated. "She and Booth are going through a very difficult time, so it's a strange time for this love from the past to show up. And it's going to have some slight reverberations. I'll be curious to see what the fans think."

Other returning characters for "Bones" season 12 includes Dr. Beth Mayer (Betty White) as well as Gordon Wyatt (Stephen Fry), Booth's former psychiatrist who is now working as a chef.