Mary Jo Walker (Janet McTeer: Waking the Dead) has a taste for contentious relationships with men. After a violent late-night argument with her latest live-in beau, Vertis Dewey (Noah Emmerich: The Truman Show, Monument Avenue), Mary Jo storms into the bedroom of her daughter, Ava (Kimberly Brown), telling her to pack her things: they're leaving, right now. But Ava is way ahead of Mom -- she's already packed and ready. "Any idea where we're going?" Ava asks once they're on the road from West Virginia, the question loaded with resigned capitulation -- we get the feeling this is a question the preteen has asked numerous times before.

But Ava's appropriate childishness is never far away. After a detour into Missouri (and more on that later), Mary Jo and Ava pore over an atlas in a roadside diner, searching for a destination for their flight. Ava lobbies for Starlight Beach in San Diego, merely because she likes the name and has never seen the ocean -- and Mary Jo agrees, both because she shares her daughter's childlike adventurousness and for lack of any better alternative.

Their journey hits some bumps in the road -- literally and figuratively -- but after a first stop at the beach for a swim, Mary Jo and Ava settle quickly into their new lives in San Diego: Mom gets a nondescript office job but makes new friends there, and Ava is really enjoying her new school and schoolmates. But Mary Jo, it seems, is constitutionally unable to be without a man -- Ava complains that her mother wants to "marry every sexy guy who comes along." And sure enough, before long, Mom is shacking up with truck driver Jack Ranson (director Gavin O'Connor) -- whom Ava immediately pegs as a "future ex-husband" -- totally subjugating herself to him, allowing herself to be talked into a financially unwise situation and even letting him tell her how to treat her daughter. Is Mary Jo's romantic cycle repeating itself again, and will it end with mother and daughter hitting the road once more?

A less astutely written script would have made Mary Jo the bad guy for leaving so many adult responsibilities to her young daughter -- watch Mom pick roadside flowers while Ava diagnoses their care trouble -- and for making Ava too aware of the adult world at such a tender age -- Mary Jo shows not the least hint of embarrassment or discomfort, for example, when Ava walks in on her and Jack in bed. But Mary Jo's relationship with Ava is too realistically complicated for that to happen here. Mary Jo becomes an idiot around men, it's true, but she's also a terrific pal to her daughter in a dynamic that many mothers and daughters will recognize, one of shared secrets and adventures that bring them uniquely close in a way that no other kind of relationship can achieve. The joyful free-spiritedness that Mary Jo and Ava have in common is beautifully depicted in scenes like the one in which they, on their cross-country drive, decide that they should start over completely fresh... and so they toss everything but the clothes on their backs from the moving car onto a deserted highway. It's a reckless and probably even foolhardy thing for two financially strapped females to do, sure, but it demonstrates a heedlessness that they have in common.

We can see that Ava, though, is not going to share her mother's attitudes about men. Mary Jo is so utterly dependent on the opposite sex that her initial thought upon leaving Vertis, in the beginning of the film, is to head for Missouri, where lives Winston. Now, Mary Jo hasn't seen Winston since high school, when he had a crush on her for "all four years" -- but that's enough of a recommendation for her. (One look at what Winston has become in the interim since high school, though, is all they need to hightail it outta there.) Ava, on the other hand, is much for deft around boys, probably from watching her mother screw things up over and over. When a boy in her new school in San Diego expresses, in typical fumbling adolescent form, interest in her, she is able to guide him through the awkward process of asking for a date without him even realizing what she's doing. Ava, we know, is going to be just fine in this department.

Honest and real, Tumbleweeds is a delight. I passed on my screener video to my best friend the moment I was done with it, urging her to watch it immediately. It's the kind of movie that you find yourself recommending to all your friends, just so they can share in the sheer pleasure of it.