Piercings, door-slamming, and mouthiness are some of the more common ways teens rebel against their parents. “Novitiate” sees 17-year-old Cathleen (Margaret Qualley, “The Leftovers”) bucking her single, vehemently non-religious mother’s expectations by training to become a nun. “I was called, and I’m gonna become a nun, and there’s really nothing that you can say that’s gonna make me change my mind,” she tells her mom (Julianne Nicholson, “Masters of Sex”) in a new trailer for Maggie Betts’ Sundance hit.

“A scholarship to Catholic school soon finds Cathleen drawn into all the mystery and romanticism of a life devoted to the worship and servitude of God,” the film’s official synopsis details. “With the dawn of the Vatican II era, radical changes in the Church are threatening the course of the nuns’ lives. As Cathleen progresses from the postulant to the novitiate stage of training, she finds her faith repeatedly confronted and challenged by the harsh, often inhumane realities of being a servant of God.”

While the plot summary focuses on Cathleen’s arc, the trailer puts Oscar winner Melissa Leo’s (“The Fighter”) character, Reverend Mother, front and center. “Since unfortunately God can’t be here to run this convent Himself, my voice will serve as a stand in for His,” she tells the postulants. Old-school Reverend Mother happens “to think the church is perfect the way it is” and is resisting pressure to reform the convent.

“Novitiate” is Betts’ first narrative feature. She previously helmed the documentary “The Carrier,” a portrait of an HIV-positive and pregnant mother, and “Engram,” a short about an elderly man and woman who reconnect after many years. Betts is signed on to direct and co-write a contemporary political drama for Focus Features next.

You can catch “Novitiate” in theaters beginning October 27.