They were practically kids, and they were sitting ducks.

In the summer of 1940, roughly 400,000 British troops stood stranded on a beach in Dunkirk, France, besieged by an advancing German army and targeted by a swarming German air force.

They had been Western Europe’s best hope for liberation. Now, pushed to the edge of the continent, they stood awaiting their fate: a miraculous rescue, or death.

Few Americans are likely to have heard of Dunkirk in the year 2017. This early episode of World War II history had fallen into relative obscurity, overshadowed by the more celebrated Allied feats at Normandy, the Battle of the Bulge, the liberation of Paris, etc.

But film director Christopher Nolan has now brought it roaring back to life in a vivid recreation on screen. His film “Dunkirk” is a profoundly gripping account of what took place on those French shores 77 years ago—and a powerful testament to the deepest bonds of nationhood.

From the very opening scene in the streets of Dunkirk, Nolan immerses us in a first-person experience that is seldom interrupted through the course of the film. Rifle shots pierce the silence. British soldiers drop like flies. A lone survivor runs for his life and hops a fence.

The British are being hunted, and we feel hunted with them.

Nolan intensifies the sense of confusion and realism by keeping us grounded in the first-person experiences of a few, and by never showing us the enemy.

Except for one momentary sight of German soldiers in the closing scene, the Third Reich remains a faceless enemy throughout the film—true to the soldiers’ experience.

To the British private, the Third Reich was a gunshot from afar, a torpedo from across waters, the deafening screech of a dive bomber lunging toward you as you stood—then ran—on the beach. The enemy is both mysterious and lethal—almost godlike. It is terror inducing.

The film could not have achieved its sensory excellence without the music score written by Hans Zimmer. Throughout the film, Zimmer’s score artfully integrates the sounds of war, creating a seamless blend that fixes the attention.

In some moments that are otherwise still, Zimmer’s pulsating beat pulls the viewer in and refuses to let us rest, putting the audience on edge for the full extent of the film.

The film score is also complemented by stunning visual work, particularly in the aviation scenes. The viewer can’t help but be awed by the skill and grit of World War II pilots, who literally chased each other down in the sky with mere bullets.

The plot of the film consists of three basic subplots that span three different periods of time—the beach, lasting one week; the sea rescue, lasting one day; and an air mission, lasting one hour.

Each subplot runs its own course, and all three meet in one epic climax at the end.

The beach subplot—already mentioned—consists of British soldiers enduring gunfire and bombing raids on the beach in waiting for a sea rescue back to Britain.

The air subplot—arguably the most scintillating to watch—follows two Spitfire pilots as they fly a mission over the English Channel. They engage in various dogfights with German planes along the way, while aiming to protect sea rescue operations happening at the water’s surface.

But the true heart of the film—and of the Dunkirk story itself—is the sea rescue mission, which ultimately results in over 350,000 British troops being saved from capture or death.

This mission is first undertaken by the British navy, which loads several large destroyers with hundreds of British troops. But these ships prove to be too easy a target for German bombers, who are able to sink several of them with relative ease.

It is here that we see true heroism of an unconventional sort on display. With naval efforts falling short, and with oil-soaked British troops jumping ship en masse to avoid drowning in a sinking destroyer, British civilians step in to save their troops.

A flotilla of civilian boats—yachts, pleasure boats, etc.—heads from the British coast into the battle zone, lifting the stranded soldiers to safety and returning them to England.

It is simply extraordinary that this feat was performed. It was, of course, no military victory—as Prime Minister Winston Churchill would note, “wars are not won by evacuations.”

But because of the unconventional heroism of hundreds of British civilians, 350,000 British troops lived to fight another day—and would eventually help win the war as part of the Allied coalition.

The lack of overt military triumph in “Dunkirk” actually serves to highlight a more enduring concept—that of nationhood.

In the modest rescue encounter between an elderly man and a group of young, exhausted foot soldiers, we are reminded of what exactly binds them together. A language. A culture. A history.

In the faces of these men, we see not a random collection of persons who just happen to live on the same piece of land. We see the deep and abiding bond of nationhood. And it is that bond that calls forth extraordinary acts of rescue from ordinary men in boats.

In a day when soulless globalism is the established orthodoxy of the West (save for Brexit and the United States in recent months), Nolan’s depiction of nationhood in “Dunkirk” is a much-needed medicine for our culture.

For that—and for a masterpiece of film—we owe Nolan heartfelt thanks.