Staff writer

‘Dunkirk” wastes no time dialing the intensity up to 11. Opening with a fleeting moment of calm, Christopher Nolan’s blast furnace of a World War II thriller introduces us — under a flutter of German propaganda leaflets falling like ash from the sky — to the British soldier who will soon become our guide through this nerve-wrackingly suspenseful telling of the events of 1940’s Battle of Dunkirk.

In May of that year, some 400,000 Allied troops had been cornered by the Nazis on the beach at Dunkirk, on the northernmost tip of France. More than 300,000 of them were ultimately evacuated, many of them by a flotilla of hundreds of small pleasure boats and fishing vessels that arrived, piloted by civilians, from across the English Channel.

Our young soldier guide to debacle-cum-triumph of the will — called Tommy and played by newcomer Fionn Whitehead — appears in only one of the film’s three parallel threads. Writer­-director Nolan simultaneously spins them into gold, interweaving time-hopping stories told from the perspectives of the stranded soldiers, an R.A.F. fighter pilot (Tom Hardy) and the middle-aged British captain (Mark Rylance) of one boat, called the Moonstone, chugging to the rescue. Nevertheless, in his nearly anonymous way, Tommy anchors “Dunkirk,” grounding it not in the forced heroics of traditional Hollywood action movies, but in an immediate and visceral sense of despair.

That fearful emotion — along with a sense of man’s smallness and his capacity for greatness — is underscored by Nolan’s very nearly impeccable technical storytelling. Reuniting with his director of photography on “Interstellar,” Hoyte Van Hoytema, Nolan frames these three stories not so much by zeroing in on Whitehead by land, Hardy by air and Rylance by sea, but, as often as not, by zooming way, way out to show us the big picture that contains all three.

Van Hoytema’s choreography of the dogfights layers close-ups of Hardy’s goggled eyes in his Spitfire cockpit with panoramic vistas of a smoking German Stuka bomber pinwheeling into the waves. Scenes of soldiers trying to sneak onto a full-to-capacity transport ship give way to overhead drone footage of the snaking lines of men waiting on the beach. And interactions set in the Moonstone’s interior cabin, where a shell-shocked survivor of a U-boat attack (Cillian Murphy) has been picked up, contrast powerfully with aerial footage that emphasizes the boat’s tininess on the vastness of the ocean. The score, by the normally bombastic Hans Zimmer, effectively utilizes sounds that aren’t even music: a ticking watch, for instance, coupled with a throbbing rhythm that sounds like the percussive pulse of your own blood rushing in your ears.

“Dunkirk” isn’t comfortable to watch; it never relents or relaxes. At the same time, it’s impossible to look away from it.

“Dunkirk” is based on an actual mission that occurred in 1940. (Melinda Sue Gordon/Warner Bros. Pictures)

This being a Christopher Nolan film, some dialogue gets lost in the cacophony of shouts, orchestral music and ambient mayhem. And the actors playing infantrymen — who include pop singer Harry Styles of One Direction, making his respectable big-screen debut — seem, at times, interchangeable.

It hardly matters, though, in a story in which plot and even character take a back seat to action on a grand, epic scale. There’s a minimalist purity to storytelling of this sort — which starts, unexpectedly, in the middle of things and charges forward toward a resolution that many of us already know. The busyness of its fictionalized, threefold historical narrative notwithstanding, “Dunkirk” plots a stripped-down course in a single direction, belying its creator’s penchant for overly complex or contrived construction.

You’ll find no flashback, no buildup, no backstory. “Dunkirk” bolts out the gate not like a thoroughbred racehorse, but like a pack of them, never stopping until — thunderingly, and with a feeling that encompasses both victory and defeat — it crosses the finish line.

PG-13. At area theaters. Contains scenes of intense warfare and some coarse language. 107 minutes.