When everything in a movie is an effect, they cease to be “special.” So limiting effects to the basics, especially in a horror movie, especially one as lean and primal as “intruders,” is how you make them truly “special” again — special and genuinely chilling.

“Intruders” is a variation on the boogeyman-in-the-closet tale. And the reality of this story about kids under attack makes the appearance of a swooping, grabbing, cowled, faceless menace all the more shocking.

The film from the Spanish director of “Intacto” and “28 Weeks Later” follows parallel stories. A little Spanish boy (Izan Corchero) of about 11 is writing a story so frightening that it gives him nightmares. “Hollowface,” the boogeyman in question, is coming to steal his face and voice in the dark of the Spanish night.

Mom ( Pilar Lopez de Ayala) is no help.

“Close your eyes and count to five.”

Then, she sees the monster and fights it off. Mom’s a believer. If only the handsome priest (Daniel Bruhl) could see what she sees, maybe he’d stop dropping his prayer and exorcism suggestions.

In England, meanwhile, young Mia (Ella Purnell) has discovered a version of the story and woven in her own touches. She polishes a draft before bedtime, and sure enough, Hollowface is on her case, too. Only his high-rise iron worker dad (Clive Owen) believes her. Yeah, he’s gotten into a fistfight with this red-hooded, no-face freak. His wife (Carice Van Houten from “Black Book”) and the cops are less sure what’s going on with this intruder.

Director Juan Carlos Fresnadillo spins this psycho-supernatural thriller into a genuine chiller, zipping us between locations and ratcheting up the fright in the scary scenes with judicious use of close-ups and strident violins in the score. It’s a scary story about loving scary stories as we watch Juan and Mia write themselves into horrific corners, perhaps taking Mia’s dad’s advice too literally.

“To kill a monster, you have to enter their story.”

I particularly like the false-alleys the film takes us into and the way it hides its mysteries. He uses train-set sized models to illustrate and set the scene as the children tell their versions of the tale. And in both halves of the story — British and Spanish (those scenes performed in Spanish with subtitles) — the child-actors are dazzlers, kids rendered speechless by the terror of what they’re experiencing. Or did Hollowface steal their mouthes?

Horror has been so dumbed down in recent years that it’s a minor miracle when a movie in this genre actually gives you something to ponder, something more than omnipotent nuts-with-knives or teenagers trapped in abandoned summer camps. With “Silent House” and “Intruders,” and last year’s “Insidious,” one can almost sense a maturing of Hollywood’s most durable genre, a desire to switch off the “Saw” and get beyond “Halloween.” Or wish it was so.

MPAA Rating: R for terror, horror violence, some sexuality/nudity and language

Cast: Clive Owen, Ella Purnell, Pilar Lopez de Ayala, Carice van Houten, Daniel Bruhl

Credits: Directed by Juan Carlos Fresnadillo, written by Nicolas Casariego and Jaime Marques.  A Millennium release.

Running time:1:41