"I think I may be beginning to disappear,” Fiona (Julie Christie) remarks to her husband Grant (Gordon Pinsent), near the beginning of Away From Her, Canadian actress Sarah Polley’s directorial debut. As Fiona, the poignantly lovely Christie -- with her blue eyes shimmering under a soft-serve swoop of grey hair -- indeed looks to be fading into the white, enveloping embrace the southern Ontario winter has formed around the couple’s secluded home. Showing the first signs of early-onset Alzheimer’s, Fiona punctures an otherwise contented dinner party by casually returning a frying pan to the freezer during the clean up.

Polley, having adapted her screenplay from Alice Munro’s short story “The Bear Came Over the Mountain,” treads lightly with the source material and with her actors, who provide a study of the slow drift of age and memory experienced by two people as one arm of their shared history races ahead toward its vanishing point. When Fiona, who aspires to “a little grace” in her decline, decides that it is time for her to be put into a full-time care facility -- the kind of place with different floors for their more “progressed” residents -- Grant is reluctant; she looks fine, better than fine, after all, and he wants to take care of her in the privacy of their own home. But when Fiona becomes lost in the landscape she has negotiated for over 20 years, and ends up contemplating the snow clouds from the vantage of a major overpass, Grant cedes defeat.

Polley captures the forced cheer and utter dejection of nursing facilities with deft instincts for small, sad, funny moments of vulnerability; the home’s director is almost villainous in her mechanical repartee, but the sight of a former sports broadcaster who never ceases commentating in vivid color while being escorted through the halls has a sad sweetness. As Fiona “progresses,” she forms an attachment to fellow resident Aubrey (Michael Murphy), who is bound to a wheelchair and never speaks, that begins to resemble that of a protective wife. Grant experiences this transfer of her affections with a wounded rue that is explained through Fiona’s increasingly cryptic references to Grant’s long history of infidelity; for years, it seems, Grant forgot his wife, and as a former English professor he can’t help but notice the dramatic irony (it’ll fuck you every time, as Dustin Hoffman noted in Stranger Than Fiction) in the idea that she can’t remember him now that his catting days are finally over.

The allusions to this defining part of the couple’s past are somewhat unsatisfying; Polley handles the heart of the film’s themes so delicately that at times they threaten to evade her grasp. Grant and Fiona have been together for 40 years but seem to have no children; a suicide attempt may or may not have led to Grant’s retirement; the seemingly idyllic nature of their relationship prevails despite what appears to be a torrid, tormented history (at one point Fiona declares some disingenuous pity for betrayed women who refuse to “play along” in the interest of the status quo). Christie and Pinsent are clearly more than capable of delving into the human muck of their characters, but for the most part are held at bay on the wistful surface. The scenes Grant shares with a nurse at the home (the excellent and credibly Canadian Kristen Thompson) and Olympia Dukakis, who plays Aubrey’s wife Marian, however, cut through the dreamy fog and have an unexpected bite more in keeping with Munro. “At the end of things,” the frank and dubious Marian says, “it’s always the men who think that not much went wrong.”

What Polley has crafted succeeds on its own merits; suffusing her frame with ethereal light, everyone and everything within is constantly on the brink of whiting out altogether. There is real grace in her portrait of a couple that stays together long enough to forget. In the figure of Fiona is the stubborn persistence not of what is remembered, however, but what is known; Christie’s eyes -- bright and empty as they train on her beleaguered husband -- still hold that core of knowledge, black and unbudging as a pupil.