For a California-raised auteur barely out of film school who hadn't set foot in his birth nation of Vietnam since age 2, writer-director Tony Bui has a remarkable, native sense of the difficult, day-to-day existence of Saigon's lower caste.

His Sundance-sweeping feature debut "Three Seasons" -- which took home the Grand Jury, cinematography and audience awards from Park City this year -- juggles a trio of deeply affecting stories, laden with powerful symbols of this nation's asymmetrical modernization and is refreshingly devoid of war references and Western perspective.

Bui uses the region's three weather cycles -- dry, wet and growth -- as backdrops for his stories, each of which represent a part of part of contemporary Vietnam's soul.

During the dry season, an impoverished and reserved cyclo driver (Don Duong) tries tentatively to romance an upscale prostitute (Zoe Bui, no relation) who has determined to marry well with one of her wealthy, mostly Western johns. In the wet season, a homeless little boy (Nguyen Huu Duoc) tries to survive on the streets after having his suitcase of salable trinkets stolen, while a world-weary former American soldier (Harvey Keitel) searches for his war-born daughter. In the growth season, an intelligent but trapped, pretty, young lotus harvester (Ngoc Hiep) befriends an aged poet, disfigured by malaria, who learns the joy of writing again by dictating to the willing girl.

Bui commands heart-bearing performances from his cast and brings these stories vividly to life with enrapturing photography (by Lisa Rinzler) that relays both the horrendous heat and dust of Saigon's streets and the contrasting luster of tourist hotels frequented by the hooker. He also captures the fantastic beauty of a lake full of blooming lotuses and the torrential downpours that make living on the city's streets such an arduous prospect. Nary an image goes to waste under the rookie director's symbolically fertile lens and nary an emotion goes unexplored in this deceptively simple film.

Aided by the influence of two high-profile project cheerleaders -- Keitel in the States and Duong (a respected Vietnamese actor who happens to be Bui's uncle) in Saigon -- "Three Seasons" became the first American production in his native country since the war (and the only US film shot ever entirely in Vietnamese).

With results like this, Bui will certainly be welcomed back if he ever decides to make another film there and, depending on the movie's success, he may have opened the door for more American funding of foreign language films. Lets hope they will be on par with this accomplished first effort.