Early in this drama about cloistered life, a nun declares, “There can be no love without sacrifice,” her words presaging the self-abnegation to follow for novices in a strict Roman Catholic order, circa 1964. A 17-year-old survivor of a broken home (Margaret Qualley) finds solace and purpose in her decision to become a “bride of Christ,” but her excessive piety alarms her protective mother (Julianne Nicholson). As the reforms of Vatican II arrive, the convent’s old-school abbess (Melissa Leo) grows cruel and erratic, destabilizing her more vulnerable charges. Writer-director Maggie Betts balances the naturalistic exchanges of her sympathetic young cast with bravura set pieces for the seasoned actors, such as Leo’s standoff with Denis O’Hare as a smug archbishop come to lay down the law.