The new film adaptation of It is just as fierce as Stephen King’s 1986 best-seller.

The aspiration is this: a Stephen King movie adaptation that actually lives, breathes, and renders you insensate from lack of sleep, just as the source material did. Stranger Things have happened. It, based on King’s 1986 best-seller that, at 1,489 pages, currently functions as a bookend for less voluminous King tomes in my library, is adamantly and terrifyingly faithful to the author’s narrative. And yes, Pennywise the Dancing Clown (Bill Skarsgård) is as joltingly nightmarish as fans could have hoped for.

While King’s book was set in the ’50s, the film loses little in its updating to 1989 and even employs a cinematically sublime specificity of time and place—A Nightmare on Elm Street 5: The Dream Child is on the local bijou’s marquee. It’s set in the seemingly bucolic but small Maine township of Derry.

Director Andy Muschietti (Mama) and screenwriters Chase Palmer, Cary Fukunaga and Gary Dauberman have managed the translation to the big screen nearly as well as Rob Reiner did with Stand by Me. And just like in that far-more-gentle—but equally spellbinding—novella and film, the protagonists are young kids, and there are dual themes: the loss of innocence alongside the pleasures and perils of youthful friendships. The difference is that It is a white-knuckle horror show blessed with an R rating, so it doesn’t have to rein in its gory, toothy terrors, like other, lesser, PG-13-rated King films must.

The story follows seven pre-internet teens as they play detective and discover—and eventually do battle with—the predatory, poisonous Pennywise, who feeds on childhood fears and is the presumable root cause of Derry’s disturbing history of unnatural deaths.

Led by melancholy, stutter-afflicted Bill (Jaeden Lieberher), who lost his little brother Georgie to the rainswept unknown, the pint-sized posse (self-dubbed the “Losers’ Club”) includes bespectacled wisenheimer Richie (Finn Wolfhard), asthmatic Eddie (Jack Dylan Grazer), orphan-by-fire Mike (Chosen Jacobs), Bar Mitzvah-stressed Stanley (Wyatt Oleff), chubby new kid Ben (Jeremy Ray Taylor) and lone girl Bev (Sophia Lillis), whose home life with her leering father is a horror unto itself.

King’s frequent theme of being young, adventurous, and more-or-less unsupervised in small-town Maine runs through many of his best stories, and It captures that same elegiac tone with poignancy.

The whole of the Losers’ Club, as well as the older bullies that constantly harass them (chief among them Nicholas Hamilton’s mulleted, knife-wielding Henry Bowers) have the unmistakable ring of authenticity. Riding their battered bicycles through the woods while trash-talking one another as only pre-digital kids could, they’re misfit knights errant on an aberrant quest, not for glory, but for their own safety and sanity.

King’s book was actually two novels in one, with the second half revisiting the adult Losers’ Club 27 years on. A sequel to It is all but assured, and I welcome it with dreadful anticipation.

It 3 stars Directed by Andy Muschietti • Starring Jaeden Lieberher, Jeremy Ray Taylor, Sophia Lillis, Bill Skarsgård • Rated R • 135 min. • At Century Cinemas Del Monte, Century Marina, Maya Cinemas, Northridge Cinemas, Lighthouse Cinemas