Oscar winner Jim Broadbent earns a fine showcase in “The Unlikely Pilgrimage of Harold Fry,” a sweet story of grief, regret, obligations and the kindness of strangers.

It’s based on a novel by Rachel Joyce that seems inspired by any number of similar “pilgrimage” narratives — “The Straight Story” to “The Way,” with a cloying detour into “Forrest Gump.” The sentiment plays. The quixotic quest at its heart — an elderly man’s impulsive walk from South Devonshire to Berwick-upon-Tweed to visit a dying woman — is dogged, scenic, patient and engaging.

That predictable turn towards “Harold goes viral” doesn’t quite spoil it. But it comes close.

Broadbent’s the title character, a set-in-his-ways OAP with a comfortable but joyless life with his brittle wife Maureen (Penelope Wilton of “Downton Abbey”) in a tidy, underdecorated semi-detached in a tidy town (South Brent, Devon).

Something broke between these two, and the ties that bind survived that. But a letter from a woman he used to work with, Queenie, has Harold taking stock. She’s dying in a hospice in the northernmost town in England, Berwick-upon-Tweed. Harold struggles with a reply letter, even enlists Maureen’s help.

“Say something you mean,” she testily advises, put on edge by the entire idea of her husband reconnecting with this woman, Queenie. As an aside, she adds that some things can’t be put in a mere letter. She comes to regret that.

But he writes that letter and walks to a mailbox, then the post office, and finally a convenience store. The blue-haired young woman (Nina Singh) there gives him more advice — another sign — on hearing of this letter to a woman dying of cancer.

“Believe you are making a difference.”

Harold resolves to go see Queenie, and on an impulse he calls Saint Benedict Hospice.

“Tell her Harold Fry is on his way. I’ll keep walking as long as she keeps living.“

He mutters the suggestion that he “let her down.” And that she’s not the only one. Flashbacks give a glimpse of a son (Earl Cave) who needed something else from Harold.

There’s nothing for it but for this elderly man in street clothes, rain jacket and not-suitable-for-a-long-hike deck shoes to walk the 500 miles, “the length of England,” to fulfill his promise.

He’s left his phone at home, which his wife figures is a sign he’s got dementia. He has no map. But south to north he goes, trekking on footpaths and B-roads and along major highways, stopping in tiny inns, flopping in barns, searching his soul for the guilt he hopes to resolve and depending on the kindness of strangers all along the way.

“You will not die, you will not die” is his walking cadence as he marches days and then weeks, pausing in Exeter Cathedral, stopping at farms, pubs and the like, “keeping to a budget” but helped by others, who take pity and rediscover their own empathy.

Maureen is instantly beside herself, then furious and whatever comes after that.

“The Unlikely Pilgrimage” is about Harold’s physical feat and a spiritual journey he and his increasingly distant wife unintentionally undertake together. And it’s about how others respond to Harold, from the helpful folks who offer him lifts which he refuses, to the immigrant doctor (Monika Gossman) who isn’t allowed to practice medicine in Brexittania, to people inspired by his quest and wanting a piece of it for their own inner peace.

Veteran Brit TV director Hettie MacDonald, with Joyce adapting her own novel into a screenplay, leans into the cute and never lets a tug at the heartstrings pass unnoticed on this journey of not just miles, but months. It works more often than not, even if its Gump-like “movement” interlude doesn’t.

But Broadbent and Wilton are the ones who do the heavy lifting here, and never for a second do they let us doubt we’re in good hands. He gives us the simple faith of acting on an impulse that Harold must do “something,” and she conveys all the hurt, confusion and panic that implies.

They’re simply great as a couple in the winter of life, struggling with the past and one last test of their relationship, people who are as likely to get the “meaning” of all this pilgrimage wrong as they are unlikely to get it right.

Cast: Jim Broadbent, Penelope Wilton, Earl Cave, Nina Singh,
Daniel Frogson and Naomi Wirthner.

Credits: Directed by Hettie MacDonald, scripted by Rachel Joyce, based on her novel. A Quiver release on Amazon Prime.

Running time: 1:48