Paranormal investigator Lorraine Warren, who has spent decades using her faith to battle demonic forces, had a ready quip when asked how she handles those who don’t believe her ghostly stories.

“Oh honey, I don’t really care. It’s between God and them,” she told Chad and Carey Hayes, the screenwriters of the new horror film The Conjuring.

The pair, who share Warren’s faith in a higher power, echo Warren’s perspective on those who don’t believe their new movie is based on actual events. They just want to start a conversation about faith and, of course, leave audiences shaking with fear.

The Conjuring, directed by James Wan of Insidious fame, recalls a ’70s-era battle between Warren (Vera Farmiga) and her longtime husband (Patrick Wilson) and a demon targeting a couple with five girls. The film recounts just one of many such adventures led by the couple, whose battles could spark a new horror franchise should the film score big at the box office.

The Hayes brothers, who previously penned films like the 2005 House of Wax remake and Whiteout, say getting to know the real Lorraine Warren helped bring color and complexity to Farmiga’s character.

“She trusted us. We birthed a friendship early on … she asked that we wouldn’t portray her in a bad way, and we assured her we wouldn’t,” Chad Hayes says.

The Conjuring may feel familiar, what with all those creaking doors and talk of exorcisms anchoring the story. The brothers say the project grabbed them when they decided against tackling the material from the typical vantage point–the poor house dwellers.

“We wanted to tell the story from the professionals’ point of view,” Chad Hayes says, adding the film’s era made that angle even more compelling.

“We were excited to do a period piece, before cell phones and all the gadgetry,” Chad Hayes says. “It’s challenging in a good way.”

The story’s spiritual component offered one final advantage for the writing team.

“The Warrens’ sharpest tool in the shed was their faith. It’s all they can depend on. It’s such a great opportunity to illustrate that without being preachy,” Carey Hayes says.

The brothers convinced Wan to take on the project after a four-hour lunch meeting.

“[Wan] never wavers. It’s like he has the eye of the tiger, he knows what he’s after,” Carey Hayes says of a director who made his name in horror by directing the first Saw entry. “He wanted to shoot the movie in order so everybody feels the tension.”

Early reviews tout that very tension, but the screenwriters are just as happy for the early notices from church-based screening audiences. Chad Hayes recalls a priest approaching him after one such screening to applaud the film’s approach to the subject matter.

“Thanks for getting it right,” the priest told him.