Excellent effects and production values and casting Krysten Ritter as a witch (Why knew?) pays off in “Nightbooks,” a Goosebumped take on Hansel & Gretel.

It’s a kid-friendly horror tale — terror with training wheels on — about children lured with sweets, trapped and forced to entertain the witch each night with new stories designed to chill, thrill and creep out.

But there’s a gaping hole in the heart of it that you can almost guess from that plot description. The stories, invented by a little horror buff named Alex (Winslow Fegley), may be somewhat fancifully illustrated — children act them out in stage fog and in front of dark, expressionistic cyclorama paintings — but are seriously lame and not remotely scary.

They sound, in point of fact, like what they are supposed to be, a child’s idea of what a scary story might be — underwritten, plot-and-setting heavy, obvious.

Alex is in mid-meltdown when we meet him, a kid whose parents are heard discussing his troubling “obsession with horror.” He’s yelling about how bad this, that or the other story he’s written is when he storms into the elevator with an idea of burning them in the basement boiler room of their apartment complex.

But that elevator never arrives. Not there, anyway. He finds himself on a darkened floor, tempted into a darkened apartment where “The Lost Boys” is playing on TV. He can’t resist taking a bite of the pumpkin pie next to the television.

And when he wakes up, there’s no getting out of this strange, many-roomed, Hogwarts maze of an apartment. A bleached blonde witch (Ritter) demands, “Is there ANYthing special about you at all?” You know, something that would cause her to “let you live?”

“I write scary stories.”

Thus begins his Sisyphean task, coming up with something out of his backpack filled with his tales that will move his sharpest critic. The witch corrects, criticizes and insults the “The Playground,” “The Cuckoo Clock” and other short stories.

Let’s just say Alex is not exactly the second coming of Edgar Allan Poe. By rights, the witch should lose patience, lose her temper and bake him into a pie or something for these seriously-lacking scribblings.

There have been other kids lured there, trapped in this apartment. He learns that from Yasmin (Lidya Jewett), another survivor. There’s also a vast repository of horror tales in this never-ending library. Some are in published books, others in notebooks, stories written by hand by other, earlier children.

In those stories, in what long-term prisoner Yasmin has picked up and in Alex’s racing mind their might be clues to a way of getting out of this perilous purgatory.

There’s a lot of goo and slime to be endured. A (digital) hairless cat who can turn invisible is prone to pooping on the kids’ PB&J sandwiches). If you’re nine, you were probably sold on the story with just that plot element.

But there are troubling other rooms and gardens and creatures — crawling, buglike story-eaters called “shredders” — to be faced and bested. And every night, the witch returns, digs into a big meal and demands to be entertained with a story. Talk about pressure.

The act of writing is hard to render cinematic, and director David Yarovetsky (“Brightburn”) doesn’t succeed where others have failed. A little boy stomping back and firth, spitballing plots and ideas? Very “writer’s room.”

Despite moments of kiddie torture, the ongoing threat posed by our witch, who “won’t just kill you” if you fail, doesn’t raise the stakes or hackles. And while the finale works up a fine level of sound and fury, it’s something even a ten year-old — or at least one who’s been read “Hansel & Gretel” — could see coming.

The idea behind this Sam Raimi-produced movie is that the next generation of horror fans have got to start somewhere. “Goosebumps” or The Brothers Grimm or J.A. White (the author of the source novel here) are just gateway drugs to “Insidious/Annabelle/Amityville/Halloween,” right?

This may very well accomplish that, and one gets the sense they signed Ritter up for a franchise. But throwing a lot of production design at the limp stories within this recycled tale doesn’t make it look or play scary. It just makes it loud and expensive looking. Cute.

Rating: TV-PG, mild frights

Cast: Winslow Fegley, Lidya Jewett and Krysten Ritter.

Credits: Directed by David Yarovetsky, scripted by Mikki Daughtry and Tobias Iaconis, based on a novel by J.A. White. A Netflix release.

Running time: 1:43