Las Vegas, 1950. The world is on the threshold of a new age. And so is Rose Chismore.

Rose, depending on your point of view, is either the flash point or the fulcrum in a family so unbalanced it makes the rest of Vegas look normal.

On one side are her mother (JoBeth Williams), a compulsive gambler whose mushroom-soup casseroles give gruel a good name, and her stepfather (Jon Voight), a shell-shocked World War II vet who worries too much about the Russians taking over the Orient and too little about his own surrender to demon rum.

On the other is her Aunt Star (Ellen Barkin), the former Miss Winnemucca, Nev., who is only in town for 42 days -- just long enough for her to divorce Uncle Frank and find a new beau.

Rose (Annabeth Gish) is 13 years old. But that's just the beginning of her problems.

Her mother is deep in debt, her stepfather is becoming abusive, her government has plans to test an A-bomb just a few miles over the hill and her first attempt at body-building takes off across a hotel swimming pool within eyeshot of the only boy she cares about.

Desert Bloom is a very intimate film, the kind that can be derived only from personal reminiscence. It shares much with films like To Kill a Mockingbird, in that it gives us a child's-eye view of events large and small, co-mingled in the context of a nearly forgotten time and place.

Las Vegas 1950 is such a time and place. Perched on the edge of the nuclear age, not yet a city and no longer a town, it's full of '50s follies, most notably a Miss A-Bomb contest, complete with Geiger-counter purses and mushroom cloud hairdos.

The genius of Desert Bloom, a 1986 independent production by Eugene Corr, is that it manages to blend the frivolous and the fearsome into a full-blown portrait of an age that, for many, was a painful as it was productive.

It's funny now to watch people "duck and cover." It's not funny to think how a whole generation came of age in the shadow of a mushroom cloud -- while the two greatest nations on earth staked their futures on mutually assured destruction.

Even so, a film like Desert Bloom would fall flat without first-class performances. Fortunately, there's no shortage of those here.

Voight is deep in character as the troubled veteran, silently loading his semi-automatic rifle in the back room while Williams warbles "Somewhere Over the Rainbow" to a parlor full of guests; and Barkin gives her role of half-tramp, half Mother Nature as many twists as she has curves.

Still, it's Gish who takes top honors with her picture-perfect pout and an uncanny ability to look 13, 7 and 62 all at once.

"Remembering was my way of making things matter," Rose tells us in the opening scenes of Desert Bloom. Just 103 minutes later it's amazing how many things she's made matter.