The Nun

Don't just stand there, sister. Act!

You know how sometimes a horror movie will have various creepy apparitions, and how it doesn’t really matter why those particular images were chosen, the point is just to be creepy? But then you know how sometimes a horror movie makes a lot of money, so Warner Bros. commissions sequels and prequels and spinoffs to provide the backstory for everything, even if no backstory was needed?

This is “The Nun,” a prequel to “The Conjuring,” explaining where the demonic nun that Lorraine Warren (Vera Farmiga) kept seeing in “The Conjuring 2” came from. You don’t need to have seen any of those movies to understand this one. You don’t really even need to see THIS one to understand this one. Set in 1952, it’s about a Catholic priest (haunted by his past, of course) and a novitiate nun who are sent by the Vatican to investigate a nun’s suicide at a forlorn Romanian castle-convent, which it turns out is home to an ancient evil. Variations of “This place is no longer holy!” constitute approximately 30 percent of the dialogue.

Father Burke (Demián Bichir) and Sister Irene (Taissa Farmiga, little sister of Vera) are led to the dilapidated convent by Frenchie (Jonas Bloquet), a French-Canadian villager who delivers supplies every week and was the one to find the body. He’s been making deliveries for two years but had never actually seen anyone come out of the place until he saw Sister Whoever hanging from the window at the end of a rope, which hardly counts. Frenchie flirts with Sister Irene and is just skittish enough about creepy stuff to be mildly comical.

The usual freaky business ensues, directed with a smidgen of atmosphere by Corin Hardy (whose 2015 debut, “The Hallow,” was better), written by Gary Dauberman (who penned the other “Conjuring” spinoffs, “Annabelle” and “Annabelle: Creation”). There are a few unsettling images — a zombie nun, a snake coming out of a boy’s mouth — but it’s hard to tell in the moment whether they’re real or hallucinatory, so we never know how much danger the characters are actually in. The story offers no scares or surprises (other than things popping out suddenly from corners), but it checks off the boxes without actively insulting your intelligence. If you want higher praise than that, sorry, you’ll get nun.

Crooked Marquee

C+ (1 hr., 36 min.; R, a little profanity, some mild violence and scary images -- really more of a PG-13.)