The Black Phone
107 minutes; R
Critic’s rating: B+

The rotary phone is back! Long live the rotary phone! Sorry, wrong number: Nobody, of course, pines for an old-school voice communication device requiring you to dial each digit in the number one at a time, and then wait for the thing to slowly spin back around before moving to the next digit.

Bonus downsides:
1)You had to pick it up and say hello before you knew who was on the other end. A romantic interest? A bill collector? Your arch rival? Your Mom, telling you to get off the phone and do your homework? Lumbergh, making you come in to work on Saturday? An evil entity from another dimension?
2) In the days of party lines, friends or foes alike could easily listen in on your conversations, unbeknownst to you, without troubling to hire a team of sweaty nerds in a surveillance van to park down at the end of your block. The Conversation,” anyone? (The visionary 1974 techno-thriller was rereleased two years ago).

Ain’t got time for all of that in the connect-right-now Digital Era. But I digress.

“The Black Phone,” the latest outing from Blumhouse Productions, best known for quirky horror movies including “Split,” “The Purge” and “Paranormal Activity,” cleverly assigns the title object a key role.

Good news: The film, which concerns itself with much more than a vintage phone, boasts the kind of originality and edginess that make for a fully engaging movie experience, and just may help it become a summer sleeper.

The most effective horror, in film and fiction, uses carefully detailed atmospherics to create a palpable mood. And the best, scariest entries in the genre also deploy the kind of suspense that serves to create creeping dread and generate occasional jump scares.

“The Black Phone,” directed by Scott Derrickson (“Doctor Strange,” “Sinister,” “The Day the Earth Stood Still”) possesses both qualities in droves.

Derrickson’s movie, adapted from a short story by Joe Hill, aka one of Stephen King‘s writer sons, is short on gore — this isn’t a by-the-numbers slasher movie or torture porn, thankfully — and long on surprises and hold-your-breath chills and thrills.

The filmmaker and his co-screenwriter, C. Robert Cargill, start strong by offering an evocative setting. It’s Denver, circa the mid-’70s. Boys with long hair, Cheech & Chong t-shirts and denim jackets variously tool around a lower middle-class neighborhood on their bicycles, get their testosterone-fueled kicks by fighting with frenemies at school, and perfect their video-game skills at the local convenience store. When not hanging with their guy posse, they flirt with girls wearing flared jeans and colorful fringed ponchos. Guitar-rock anthems like the Edgar Winter Group’s “Free Ride” and Sweet’s “Fox on the Run” rule the airwaves. Pink Floyd is in the mix, too.

The look of the film, washed-out and grungy around the edges, enhances its feel; it’s a bit reminiscent of movies made during the time when this movie is set. Occasional gritty dream sequences, images of family life and evil goings-on akin to spooky home movies, inject a true-crime vibe into the goings-on. Are we watching a partly fictionalized “Dateline” account of something wicked that came this way a half-century ago?

At the center of the story are Finney (Mason Thames), a smart kid who’s obsessed with NASA and space exploration, and is frequently bullied by dumb tough boys. He’s routinely shadowed by his take-no-prisoners little sister Gwen (Madeleine McGraw). The two rely on each other to navigate tricky social terrain at school and deal with the unstable behavior of their abusive single father (Jeremy Davies). His alcohol-fueled grief over the death of his wife, the kids’ mom, sometimes metastasizes into angry tirades and violence against his own children.

The siblings, too, live in a world threatened by an ongoing tragedy: Area boys keep disappearing, as we learn via “missing” flyers, eerie nighttime neighborhood searches, and the haphazard investigative work of a pair of not-so-bright police detectives sporting period-appropriate bad haircuts, ill-fitting suits and wide ties. They repeatedly badger Gwen over why she knows certain details of a recent disappearance that were never released to the press.

It’s impossible to reveal much more about the narrative without spoiling the pleasures of this type of film. Suffice it to say that “The Black Phone” imaginatively combines a flesh-and-blood crime mystery with supernatural elements — some sequences are reminiscent of “The Sixth Sense” — and does so seamlessly.

Thames and McGraw are real finds. The young actors handily hold attention during their scenes alone and together; these somewhat naturalistic turns feel like break-out performances.

Ethan Hawke, so brilliant as abolitionist John Brown in Showtime’s recent “The Good Lord Bird” series, and a revelation again in Paul Schrader’s “First Reformed” (2017) here is cast against type. It’s a reunion with Derrickson and Cargill; the three worked together on the director’s “Sinister” (2012).

Hawke primarily uses his voice and body language, almost never showing his full face, to create one of the creepiest and most frightening movie villains of at least the last decade. “Hold my beer,” says Hawke’s The Grabber to the clown from “It,” penned by Hill’s famous dad.

Yes, as filmgoers probably already know from seeing the film’s poster or trailer, fiendishly scary masks are involved. Be afraid. You know you want to.