At the beginning of the South Korean spiritual horror Dark Nuns, Sister Yunia (Song Hye-kyo) attempts to drive evil out of a boy named Hee-jun (Moon Woo-jin) who is possessed by a demonic entity.

She draws troubling images and is uncomfortably close to a creepy nun (a requisite of this subgenre), whose high-pitched giggle is like nails on a chalkboard. While a fellow novitiate (a beguiling ...