Our motives and emotions aren't always wrapped in a tidy package, and one of the beauties of Krzysztof Zanussi's "A Year of the Quiet Sun" is that it preserves some of the mystery of why we do what we do. Set in post-World War II Poland, "A Year of the Quiet Sun" (the title is an obscure astronomical allusion) is a magnificently crafted essay on love and hopelessness, rich with history, alive with the struggle of beauty.

At the outset, Norman (Scott Wilson), a U.S. Army private, decides to stay in Poland as a driver for American observers in a war crimes trial -- he's got nothing to go back to. Quite by accident, he meets Emilia (Maja Komorowska); he's urinating on an abandoned automobile at the roadside, only to discover that she's sitting with her canvas and brushes, painting a sunrise, inside. Though she's no beauty, something in her face, her manner, speaks volumes to him. When he chances to see her again, bicycling through town, he trails in his jeep, and begins his courtship.

Of course, she speaks no English; he, no Polish. Part of the magic of "A Year of the Quiet Sun" is the way the rapport between Norman and Emilia, forced to proceed without language, ends up transcending it. Their dialogue of glances and smiles, of wordlessly shared secrets, has a marvelously childlike quality -- they become innocents. And Zanussi cleverly exploits the comedy of the situation -- when translators are brought between the two lovers, they're invariably incompetent. Norman pledges his love, and in a translator's mouth, it becomes, "He said that he had money to sneak you and your mother across the border." For Zanussi, an artist in today's Poland, words don't express the truth, but rather hide it.

It turns out that what Norman saw in Emilia's face in that first meeting were the wounds of a fellow survivor: Emilia and her mother (an engagingly tough Hanna Skarzanka) had spent the war in a concentration camp; Norman was a prisoner of war, tortured and humiliated by the Nazis. Love, then, and hope are almost intolerably precious to them, a sense that pervades both Wilson and Komorowska's performances.

There's a softness, a lanolin gentleness, to the cast of Wilson's face here -- he always seems on the verge of tears. As Wilson paints him, Norman isn't the brightest guy in the world, but he's surely the most tentative, an inveterate stammerer. His first meeting with Emilia, for example, goes like this: "Sorry. Aaaaaaah. Sorry. Aaaaaaah. You aaaaaah. Excuse me. You paint. Pretty. Aaaaaah." What's marvelous about Wilson's performance is the way he's able to make the stammer a metaphor for Norman, to take Zanussi's theme of the failure of language and put it to use -- he's like a baa-ing sheep. And all of this goes for Komorowska as well -- in a way, her performance is a meticulous mirror image of Wilson's, with the same skittishness, the same sense that the world is one big hot stove to get burned by.

"A Year of the Quiet Sun" is beautifully photographed -- you sink comfortably into the mauve and green nighttimes, the brown, dimly lit rooms -- and the hand-held, documentary-style camera lends the movie an aura of reality. What makes it more extraordinary is that Zanussi used all the film he shot, without the Hollywood luxury of culling a movie from 100 hours of footage. Zanussi isn't Gen. Jaruzelski's favorite filmmaker -- the war crime in the film's background evokes a massacre of pilots that was actually perpetrated by Russians, not Nazis; the local Communists are presented as thugs; and altogether, the picture deviates from the party line that presents the postwar period as the cheery advent of socialist paradise. Then again, Jaruzelski isn't one of Zanussi's favorite generals. Loss, in "A Year of the Quiet Sun," isn't personal, but national and, ineradicably, part of life.

A Year of the Quiet Sun, opening today at the Key Theatre, is unrated and contains some scenes of the exhumation of corpses that may be troubling to children.