Rated 3.0

In a small South Korean town, a woman’s maternal devotion goes into high gear when her mentally challenged son is accused of murdering a schoolgirl. Director Joon-ho Bong’s film (co-written with Eun-kyo Park and Wun-kyo Park) begins as a sad-sack comedy, then switches to a kind of Asian noir murder mystery, before finally winding up as a bit of an anticlimactic shaggy-dog story. Remarkably enough, though, Bong manages the transitions so smoothly, and garnishes his movie with such fascinating character touches and vignettes of urban Korean life, that we don’t feel cheated when the story winds up more or less where it began. Hye-ja Kim brings a dogged determination to the role of the mother, and Bin Won plays the son with an artless canniness that suggests the boy isn’t quite the dummy others think he is.