There is an early scene in this movie which shows the main character, Mary Jo Walker, throwing all her clothes out of a car window and letting them fly off down the highway. She's trying to make a point to her daughter about how they should leave their old lives behind and look forward to the future. Never mind that she has no money to buy new garments -- she's being carefree, everybody!

Moments like this don't exist in the real world, and for all its dirty locations and documentary-style hand-held camera movement, hardly a second of "Tumbleweeds" does. It resides in that particularly farfetched cranny of Hollywood where audiences are expected to root for obnoxious trailer trash sluts like Mary Jo simply because she keeps saying "I'm gonna get me a new life, yessir!"

The woman is played by British actress Janet McTeer as someone who cannot settle down even after childbirth, four marriages and numerous attempts at relocation. She's leaving one of her husbands as the movie opens, and young Ava (Kimberly J. Brown) seems to know the drill, getting from the house to the car so fast it's as if she'd expected the break-up sooner, and had been getting impatient.

The plot goes through the same motions as all other mother-and-child road movies, which range from "Alice Doesn't Live Here Anymore", released in 1974, right up to last year's "Anywhere But Here". We know certain obligatory things must happen: The mother's recitals of lines about how things can only get better. The child's groaning, complaining and rebelling. Comic relief in the car. Sentimentality in motel rooms. Pigging out after mom gets her first new job. Romance, separation. More romance, another separation. Reunion. Happy ending. (Yippee.)

There are some good things about the film, including McTeer's Oscar-nominated performance. She never makes Mary Jo likeable -- that would be an impossible task -- but her American 'Southern belle' accent is faultless, and she follows a set of mannerisms so subtly distinctive that it's hard to deny she has inhabited the character. Even greater kudos to Brown, who is just as convincing in a more emotionally complex role, wanting to love and support her mother, but often feeling neglected and unguided by her.

Several good passages of dialogue can also be found in the picture -- one involving "coffee enemas" will not soon leave my memory. But little moments such as these don't quite conquer our animosity toward Mary Jo, who is an insecure tramp, ill-equipped with parenting skills and lacking in self-worth. Enjoyment of "Tumbleweeds" requires us to abandon logic and values from the real world, so we can blindly cheer on the characters. We're supposed to feel happy, for example, when Mary Jo walks out on her typing job at an alarm company, destroying lots of files on the way out. But would you really be happy if YOUR security details were destroyed? Methinks not.