“ORDINARY LOVE”

** 1/2

(R, 1:32)

Tom and Joan are a long-married couple whose daily routines — walking for exercise, shopping for groceries, trading affectionate pretend insults — signal deep affection and easy intimacy. The movie about a trying year in their lives is called “Ordinary Love,” and the opening scenes paint a modest, careful picture of unexceptional middle-class existence.

The catch — and also the point — is that these unassuming people are played by two extraordinary actors: Liam Neeson and Lesley Manville. The film, directed by Lisa Barros D’Sa and Glenn Leyburn from a screenplay by Owen McCafferty, is nearly a two-hander, and the hands are played with discipline, grace and wit. Neeson, taking a break from his usual wintertime angry-dad action-movie duties, is wry and crinkly, his loose limbs and craggy features suggesting great power in repose. Manville is a sharp, quicksilver presence, her face hovering between impatience and astonishment. The two of them communicate absolute trust in each other, and inspire the same in the audience. You are prepared to believe everything they say and do.

But you may also wish there were more. The narrative of “Ordinary Love,” which stretches between two Christmases, deals with what happens after Joan finds a lump in her left breast. There are tests, more tests, surgery and chemotherapy — the grim, anxious, absurd routines of modern cancer treatment.

“There won’t be a minute that I won’t be there with you,” Tom promises, and though he is true to his word, Joan’s illness subjects their relationship to complicated stresses and shocks. They are going through it together, but in a cruelly asymmetrical fashion. The caregiver and the patient are allies, but neither one shares the other’s particular suffering, which threatens to turn them into adversaries.

D’Sa and Leyburn (“Cherrybomb,” “Good Vibrations”) convey this with a sensitivity that is both admirable and frustrating, casting a tasteful, restrained hush over potentially unruly emotions. The music (by David Holmes and Brian Irvine) modulates from nervous to soothing to sad, and the editing (by Nick Emerson) folds one scene tactfully into the next. It has often been said that war movies inevitably glorify combat, and it’s also true that movies about grave illness tend to sentimentalize its ravages. That is the case here: An experience often defined by dread, indignity and tedium is softened and made beautiful.

There are, nonetheless, a handful of scenes that have the rough, tender pulse of real life. The major problem is that, beyond the cancer and their devotion to each other, Tom and Joan seem barely to have lives at all. We know that they had a daughter, named Debbie, who died, though we don’t know how or how long ago that tragedy occurred. Tom and Joan have, as far as we can tell, no other family, no jobs and no friends, though they do strike up an acquaintance with a couple they meet at the hospital.

Tom feeds the fish in his aquarium, and he and Joan take daily power walks and squabble about nutrition, but any cultural interests or political opinions they might have remain unspoken. Or else left blank by the filmmakers, who depend on Neeson and Manville to fill in the script’s empty spaces with the force of their personalities. It almost works.