“There’s something WRONG with the new babysitter!”

Jacob (Joshua Rush) is just a tween, but he’s got clues.

“Anna” is letting them tear up stuff to make costumes, paint on the walls. She tells them a bedtime version of “The Three Little Bears” that’s hand-drawn and oh-so-DARK.

Hide and go seek just gives her the chance to look the place over, find the family’s strong box, learn its secrets.

“Mom and Dad aren’t HERE now,” is her only rule.

Sometime between “Let’s see what happens when we drop your hamster into the constrictor’s tank” and “Let’s watch mom and Dad’s homemade porno,” Jacob puts it all together. Anna is NOT angling for a tip.

“She’s not a REAL sitter!”

“Emelie” is a short, slow-building nightmare built around an exceptionally creepy turn by Sarah Bolger (“The Spiderwicke Chronicles,” TV’s “Once Upon a Time,” “The Tudors”).

We’ve already seen the “real” Anna snatched in the opening moments. We’ve seen Fake Anna wipe the blood off her shoes and shout “Bye, Mom!” into the stranger’s house she was sitting on, waiting to be picked up by the kids’ father.

And we’ve gotten a very bad vibe from this stranger with the sweet, disarming smile the moment she asks the parents (Susan Pourfar, Chris Beetem) an odd question on their way out the door.

“Do the kids have their own phones?”

Anna watches the parents drive away, locks the kids in for the night. Let the “games” begin.

Music video and TV commercial director Michael Thelin, working from a textbook lean, suspense-building script by Richard Raymond and Harry Herbeck, is grudging with his frights in the early acts.

Bolger turns a cruel come-hither look on young Rush, and a callous “things die” cruelty on Carly Adams and Thomas Bair, who play the younger siblings. She has essentially two jaw-dropping moments to play, and knocks both of them out of the park.

When Emelie invites Jacob into the bathroom with her and gets him to locate a femine hygiene product, you know he’s either got a story his tweenage buddies will never believe or that he’ll be scarred for life. Emelie has an idea just how long that “life” will be.

The foreshadowing is entirely too on the nose, and the “explainer” flashbacks almost unnecessary.  But “Emelie” is a jarring, jolting entry in the “Hand that Rocks the Cradle” genre, a too-obvious thriller that still lands a sucker punch or three.

MPAA Rating: TV-MA

Cast: Sarah Bolger, Joshua Rush, Thomas Bair, Carly Adams, Susan Pourfar, Chris Beetem

Credits:Directed by Michael Thelin, script by Richard Raymond and Harry Herbeck. A Dark Sky release.

Running time: 1:22