A film of consequence and warning, Kenneth Branagh’s “Belfast” takes us back to the beginning of “The Troubles” in Northern Ireland and lets us see them through the eyes of a little boy. A very personal story equal parts pathos and warmth, it sentimentalizes the region’s “Bad Old Days” even as it reminds us and “them” that nobody wants to go back there.

In cinematic terms, it’s starkly beautiful and achingly-dramatic, a showcase for Oscar-worthy performances by Caitriona Balfe and the great Irish character actor Ciarán Hinds and a victory lap turn by Dame Judi Dench. For director Branagh and his movie’s co-star Jamie Dornan, it’s a reminder of their gifts and robust, redemptive return to form.

The thesis is set up in a simple, symbolic opening — a tourism commercial drift through the colorful, vibrant Belfast of working shipyards full of cruise ships, high rises, memorials and museums for tourists. And the color drains from the screen and we return to the stark and white of August 15, 1969.

The streets are teeming with kids playing, parents shouting “Come home for tea,” and other adults and kids passing on the messages to children beyond earshot in Grove Hill.

Everybody knows everybody else, “It takes a village” is in the DNA, and Protestant and Catholic doesn’t matter.

Ma (Balfe, of TV’s “Outlander”) summons her sons, the tween Will (Lewis McAskie) and pre-tween Buddy (Jude Hill). Buddy is the one who tarries. He’s the one transfixed and then terrified by the sudden intrusion of masked men, hurling rocks and abuse, throwing Molotov cocktails and smashing select businesses and targeting people, houses and cars.

It was Northern Ireland’s Kristallnacht, only it happened in broad daylight.

The terror goes on after Ma plucks Buddy from the mayhem, the children cowering under the dinner table as Ma and her in-laws (Dench and Hinds) stare in disbelief. As news reports flicker on the TV and a journalist gives an Edward R. Murrow-styled account of what he saw on the radio, the locals — Protestant and Catholic — scramble to clean up and build barricades against the next, because “the police won’t protect us.”

It’s bad enough that Da (Dornan, putting “50 Shades” 50 years behind him), who does joinery in the London construction industry, rushes home to see to his family.

“I think you’ve got a few big decisions to make, son,” his Pop (Hinds) counsels, seated on the outdoor toilet in their backyard.

Little Buddy overhears this, asks Granny the who and the why of it all — “They’re friends, family, just like us” she says of both Catholic victims and Protestant perpetrators. This “nonsense’ll stop soon enough.”

“Was that our side?” Buddy wants to know.

“There is no ‘our side’ and ‘their side,'” his father corrects him. “Didn’t use to be, anyway.”

The family dynamic is established. The pull of family and community is strongest in Ma and the kids, who resist uprooting. Da and Ma argue about their crushing debts and circumscribed future and he pushes for “a new start” — in London, Sydney or Vancouver.

Buddy consults with whimsical Pop about “maths” and a girl he has a crush on in school, with Granny interjecting just as whimsically.

Da is threatened by the local Protestant ringleader (Colin Morgan) with a “You’re either with us or against us,” promising to involve even their children in this “cleanse the neighborhood” violence.

“It’s a mad world.” “Get used to it.”

And Buddy, picking up on real-life trauma and archetypal themes from Westerns like “The Man Who Shot Liberty Valance” and “High Noon” on the telly, struggles to make childish sense of it all as Van Morrison songs of the day waft out of radios and well up on the soundtrack.

A fire-and-brimstone preacher blazes away veiled references to the damnation of Catholics from the pulpit, a veritable call to arms that scares the kid and confuses him further.

Perhaps the cousin (Nessa Eriksson) who walks him to school can help. There’s comical misunderstanding and over-simplification of Catholicism everywhere. You can tell “us” vs. “them” by “their names,” Cousin Vanessa assures him. But as he swats down “But this” or that person in their own family has that name, she’s shut up and he’s dismayed.

“How the hell y’supposed to know them?”

And older folks, from aunts and uncles to Pop, rhapsodize away the trauma Ma sees in the very idea of “going over the water,” uprooting themselves from their community, their history and their lives at this bad situation that they all sense and history showed was just going to get worse.

“The Irish were born for leavin’.”

Young Hill brings the wide-eyed innocence you’d expect to his role as basically the audience’s surrogate, the innocent who has to have everything — love and women, geography and genealogy — explained to him. Balfe brings a mercurial fire to Ma, a woman truly torn even though they’re “drowning” here and living with her in-laws.

Dornan’s Da is both bluff and frightened at any turn of events he can’t protect his family from, brushing away his “do the horses” (gambling) and absentee parenting, flinty with this the guy everyone knew as a neighborhood goon and alarmed at the power the punk now has over them all.

Dench’s misty-eyed Granny is another grand, heartbreaking turn on her resume, a stoic woman whose ex-coal miner husband is sick with her son struggling to get his family out. And Hinds adds a glorious twinkle and sentimental spark to every scene he’s in. It’s a grand and warm showcase for an actor with a career (“Munich,” “In Bruges,” “Persuasion”) of hissable villains, conflicted heroes, tentative lovers and sturdy heroes.

Sometimes Branagh gets carried away with the sentiment, a little too on-the-nose with Van Morrison hear, a musical wake that seems more like a scene from “The Commitments.” But the personal nature of the story and the child’s point-of-view wash over that because this is the way memory works and childhood — even one as traumatic as living through “The Troubles” — becomes idealized.

“Belfast” is a moving, tense and yet often lightly comical experience. And as one of the best pictures of 2021 ends, you remember how good a filmmaker Branagh can be, and marvel at how he was able to pack all this warmth, wit and trauma into just 100 minutes.

Rating: PG-13 for some violence and strong language

Cast: Caitriona Balfe, Jamie Dornan, Ciarán Hinds, Jude Hill, Nessa Eriksson, Lewis McAskie, Colin Morgan and Judi Dench.

Credits: Scripted and directed by Kenneth Branagh. A Focus Features release.

Running time: 1:38