Wendy and Lucy (R) ***½

As far as traditional plots go, hardly anything happens in Wendy and Lucy: This is essentially the story of a girl named Wendy (Michelle Williams) who looks for her lost dog, Lucy, only with less of the angst and drama even that simple scenario implies.

But within the confines of this minimalist (with a microscopic m) picture, there are sequences so vital, timely and of-the-moment, so powerful and well-observed and precise, the effect can be emotionally overwhelming.

Director Kelly Reichardt (Old Joy), adapting a short story by Jon Raymond (who co-wrote the screenplay), embraces the unadorned simplicity of her source material, opting to leave out details most other filmmakers would be tempted to overstate. We never learn, for example, what led Wendy, who is driving through the Pacific Northwest toward Alaska in hopes of finding work, to become destitute, living out of her beat-up Honda Accord.

We never find out, either, why the seemingly normal and intelligent Wendy appears to be utterly friendless and alone: When she uses a pay phone to call her sister in Indiana, the resulting conversation suggests a bitter, long-standing estrangement.

Wendy's only companion -- the only thing that ever inspires a smile -- is her beloved Lucy. But even that source of happiness is taken away after Wendy is arrested for shoplifting, and Lucy, left leashed outside a supermarket, disappears.

The rest of Wendy and Lucy follows the young woman as she tries to find her dog and repair her stalled car. Reichardt uses her heroine's quest to illustrate the plight of the disenfranchised on the economic fringes of a society that doesn't know what to do with its dropouts. Without even a phone number of her own, Wendy is treated as a ghostly non-entity by practically everyone aside from a parking lot security guard (Walter Danton), although he, too, initially marginalizes her.

Played by Williams (Brokeback Mountain) as a scrappy and resourceful survivor who refuses to wallow in self-pity, Wendy is an immensely sympathetic character, even if we never fully come to understand her (why, exactly, didn't Wendy do something to keep her life from deteriorating to its dire condition?). And Reichardt's compassion for her protagonist permeates every frame of the movie, which ends on a perfect note of heartbreaking poignancy that illustrates the sacrifices we sometimes have to make in order to eke out an existence.

Cast: Michelle Williams, Will Patton, Walter Danton, John Robinson, Larry Fessenden.

Director: Kelly Reichardt.

Screenwriters: Kelly Reichardt, Jon Raymond.

Producers: Neil Kopp, Anish Savjani, Larry Fessenden.

An Oscilloscope Pictures release. Running time: 80 minutes. Brief vulgar language. In Miami-Dade: Intracoastal; in Broward: Gateway; in Palm Beach: Mizner Park, Lake Worth Playhouse.