Holy incestuous drama! “If There Be Thorns,” the third installment in the V.C. Andrews’ “Flowers in the Attic” series, premiered on Lifetime Sunday night. The latest adaptation not only reunited viewers with an older Cathy (Rachael Carpani) and Christopher Dollanganger (Jason Lewis), but it also introduced fans to Cathy’s two sons – Bart (Mason Cook) and Jory (Jedidiah Goodacre). The story was no longer about Cathy and Christopher fighting their romantic feelings for each other, but instead the brother and sister trying to live with their “sins” and protecting their children from the horrors of their past.

Unfortunately for the Dollanganger siblings, their dark secret didn’t stay hidden. Their estranged mother, Corrine (Heather Graham), moves in next door and set off a series of events that ultimately forces Cathy’s youngest son, Bart, down a twisted and troubled path.

One of the most dramatic and frightening scenes in the “If There Be Thorns” movie involves Bart and his adopted sister, Cindy (Bailey Skodje).  Viewers will remember that a jealous Bart returns home to find the young girl playing in a kiddie pool with a doll and singing “Twinkle, Twinkle, Little Star.” Bart catches little Cindy off guard when he verbally and physically attacks her.

“She’s not your mommy and I’m not your brother,” he yells at her. “And you’re not part of this family.”

In a move that surprised viewers, Bart pushes Cindy under the water in an attempt to drown her. The little girl flails for a few minutes before Jory manages to rescue her from Bart’s grasp. Cathy and Christopher was horrified to find that their son was capable of such a frightening act -- and Bart showed no remorse. When told that he should love his sister, Bart counters that “brothers shouldn’t love their sisters.”

“Isn’t that right, Chris?” he questions his step dad.

Chris threw Bart up in the attic to think about his actions, but that only spurred the young boy to start spouting hateful words about how his parents were sinners and the devil’s spawn.

The scene was not just frightening for “If There Be Thorns” fans to watch – but also for the actors to film.  Rachael Carpani revealed to the International Business Times that the scene was “far more disturbing” to shoot.

“We didn’t realize how disturbing that would be,” she explained. “Obviously it was all very safe. They had props to use and a robotic doll as well.”

Although the actress playing Cindy wasn’t involved in the filming of the frightening scene, Carpani said that they took the time to explain to her that everything as safe.

“Jason [Lewis] and I had to run out of the house at that exact moment just so that Bailey wasn’t afraid or anything like that,” she added. “We did that reaction in one take. We were watching it on the monitor and it was really disturbing.”

Mason Cook, the actor who plays Bart, can be thanked for making the scene so chilling.

“He was fantastic,” Carpani said of her young co-star. “It really rested on his shoulders because he had to set it up.”

Fans of the “Flowers in the Attic” series will be able to see Bart’s tale progress when the fourth installment, “Seeds of Yesterday,” premieres on Lifetime Sunday, April 12 at 8 p.m. EDT.