When the babysitter stumbles upon a crazed woman devouring the kid she’s supposed to be caring for in the opening moments of “The Wretched,” my first thought was “zombies” and second thought was “vampires.”

Silly me. WITCHES. The feminine evil you can ward off with salt, kill with fire, those folks.

Besides, the Pierce brothers, veterans of all sorts of film set jobs before jumping into directing, already made their zombie movie — “Deadheads.”

“The Wretched” is a polished reasonably tight tale of a witch infestation coming to rural, lakeside Michigan, and the teenage boy who screams “Why won’t anybody BELIEVE me?”

The picture’s sheen doesn’t hide the script’s grim inevitability, its deer skulls and witching tree and witch hole in the heart of the woods. But it does tend to distract from the umpteenth tale of the kid who sees what the grownups are up to and struggles to save the littler kids from devouring by the ladies who like brooms.

Not that we see any of those. This isn’t “Wizard of Oz.” It’s “dark,” which passes for sophistication in the genre.

Ben (John-Paul Howard of TV’s “Cheerleader Nightmare”) is the boy who shows up for the summer, not-really-ready to work for his dad (Jamison Jones) at the (Northport, Michigan) marina. He’s got a busted arm.

Still, friendly-sassy Mallory (Piper Curda) is there to guide him through.

And after hours, there’s all the weird and randy goings-on from the summer rentals next door. Tattooed mama Abbie (Zarah Mahler) grew up there, and when she isn’t scaring her little boy, Dillon (Blane Crockarel) in the forest, she’s gutting the deer they hit on the drive home.

“You should have seen at her burning man,” Dillon’s dad (Kevin Bigley) cracks. “Mom’s always been weird.”

And that’s not the half of it. When we hear that clicking growl from the “Predator” movies, when we see flowers wither in her presence and see that reassamble-the-bones back and neck-crack to stand upright (a horror movie staple) we know something’s moved in on Abbie.

Ben finds himself fretting for Dillon and freaking out on “witchlore” websites as he pieces together what he thinks is happening with the neighbors. But he’s up against it.

The “witch” takes over host bodies. The “witch” bends minds in that “These are not the droids we’re looking for” way, makes people forget what they’ve seen, or even that they have children.

Because the witch, as any Hansel and/or Gretel could tell you, craves children.

The story’s few distractions include bullying by the rich kids, teen drinking and panting for Ms. Wrong when Ms. Right, who knows “port” from “starboard” and other boatways, is right in front of you.

The acting’s not bad, the production values solid. But “The Wretched” is never more than a horror thriller you don’t mind as opposed to one worth tracking down. Except for one thing.

It streams May 1. But it also heads to select American drive-in theaters, the safest way to “go out and see a movie” these days. This beast, with its monsters and witchcraft and dating dos and don’ts, was made for the drive-in.

MPAA Rating: unrated, gory violence, teen drinking, nudity, profanity

Cast: John-Paul Howard, Piper Curda, Jamison Jones, Zarah Mahler and Blane Crockarell.

Credits: Written, directed and produced by Brett Pierce, Drew T. Pierce, The Pierce Brothers. An IFC Midnight release.

Running time: 1:36