Deceptively simple and rather crudely structured by American movie standards, "Yaaba" is nonetheless a striking, compelling treatise on human values by African filmmaker Idrissa Ouedraogo.

His story focuses on a 12-year-old boy named Bila who reluctantly enters into a friendship with an ostracized old woman named Sana. She has been relegated to living on the outskirts of the local village in the Sahelian desert. Why is not explained until the film concludes . . . though rumor has it she is a witch.In the opening sequence Bila and his cousin Nopoko are playing in the barren landscape when they wander over to the local graveyard where Nopoko mourns her long-dead mother. While there they spot Sana and mutter about her being a witch, but then she approaches them and makes a kind gesture toward Nopoko.

Later in the film Bila becomes angry when the local bullies throw a rock at Sana and injure her forehead. And through these and other simple, day-to-day events Bila and Sana begin to form a bond - which causes the gossiping neighbors to deride them both.

Eventually, Nopoko becomes ill and Sana is blamed. Even when she brings in a well-known healer her efforts to help are rebuffed. Bila manages to intervene, however, and brings the healing medicine to Nopoko.

All of this is played out quite naturally, along with such subplots as the relationship between Bila's gruff father and gentle mother, the gossipy neighbor who causes trouble for everyone and a young woman who cheats on her older husband because he is an impotent drunkard.

As you might guess, despite the unusual setting of a poverty-ridden African village, the people and their problems become universal characters.

It's apparent many if not all of the players are not professional actors and there are places where that becomes a serious weakness. And Ouedraogo's pacing is sometimes a little off, allowing the film to drag here and there.

But on the whole "Yaaba" - which, in the Moore language used here, means "Granny," a term of endearment used by Bila for Sana - is perceptive, entertaining and most enjoyable.

"Yaaba" is not rated but would probably get a PG for a few profanities, some mild violence and implied sex.