The Following: Does Joe Carroll Have a New Protégé?

The Following's Joe Carroll (James Purefoy) fell off the "let's not kill people" wagon on  last week, and it looks like he'll be getting the hell out of dodge Arkansas post-haste to reunite with his followers in New York City. But will his adopted daughter of sorts, Mandy (new cast member Tiffany Boone), go with him?

"You will be very surprised by Mandy," Boone tells TVGuide.com. "I think [Monday's installment] is the episode that defines who she is and who she's going to be for the rest of the season. I was shocked by the things that she does and decisions she makes, and I think the fans will be too."

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After having Joe (a.k.a. "Darryl") live with her and her mother Judy (Carrie Preston) for the past year, Mandy has come to see the serial killer as a father figure, according to Boone. "Mandy is a young girl who's really impressionable," Boone says. "She grew up without a dad. She grew up without a man to lead her. And this person comes and cares about her and has all day to spend with her and teach her things and read with her. So, she will follow him anywhere because it's the first time that anyone genuinely cared about her. ... Everyone who becomes a follower is missing a leader, a place to belong. And he reads you and he makes you feel like you're wanted."

Though 15-year-old Mandy seemed completely horrified when she witnessed Joe committing his first murder in a year last week, Boone says the relationship her character has established with the cult leader clouds her judgment. "I think she believes that the things that he does come from a good place," Boone says. "She believes in the idea that, as he says, when he kills someone, that he's releasing them and that he's giving them a gift. ... I think that gets more complicated as the season goes on and she starts to question a little bit. But she loves him so much that she pretty much thinks that everything he does is perfect."

One person who probably won't take kindly to the presence of a new protégé in Joe's life is Emma (Valorie Curry), who's only just found out that her former mentor/lover is still alive. But don't look for Mandy to take Emma's place, according to Boone. "Emma's relationship with Joe is the most important relationship that I think we see him have this season," Boone says. "[But] you will see Mandy and Emma meet up, and they have a tumultuous relationship for sure."

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Monday's episode also offers more insight into Mandy's strained relationship with her mother, a follower of Joe's who wrote him letters while he was in prison. "It's just the two of them, and Mandy hates where she grows up," Boone says. "She doesn't have a lot of friends. Joe kind of becomes her only friend. And there's a lot of men in and out of her house because her mother's a prostitute. So, while I think that Mandy and her mom are close, neither one of them are happy."

It seems like Mandy would seize the chance to leave her lackluster life behind her, and judging from the exclusive sneak peek below, running away with Joe might seem like nothing less than a golden opportunity for her. But at what cost?

"I think Mandy's a good person on the bad side," Boone says of her character. "She kind of blindly follows [Joe] into a lot of sticky situations, a lot of situations that pressure her to grow up faster than she probably should be. ... She's challenged to make a lot of really difficult decisions in a short period of time."

Check out an exclusive clip from Monday's episode, "Trust Me," below:

The Following airs Mondays at 9/8c on Fox.