L.A. Under an Inversion Layer of Dreams : WHITE HORSE CAFE <i> by Roberta Smoodin (Penguin Books: $6.95; 256 pp.)</i>

What Roberta Smoodin does in her new novel, “White Horse Cafe,” is take a group of losers and their failed dreams and tries to make them and their lives not only interesting, but heroic.

Always a tricky proposition.

Take Sasha for example. She has no idea what her real name is or who her natural parents are. She abandoned her adoptive parents when she was in her teens keeping only their last name, Berlin, which she thinks makes her sound “vaguely exotic.” Sasha has big bones, blond hair, blue eyes and calls herself an actress. She is really a waitress.

And there is Tomas. A Mexican who doesn’t look Mexican “except, perhaps, for his imperial, the dot of facial hair below his lip, above his chin,” he drinks tequila and smokes a lot of dope. Tomas is the grandson of a famous Mexican general and believes he has “the blood of warriors in his veins.” The truth is that he runs El Caballo Blanco, a restaurant owned by his grandmother.

Sasha, the woman with no family history, lives with Tomas and thinks one of the reasons he loves her is that, unlike Tomas, “I’m completely empty of stories. There is nothing epic about me.” One of the reasons Sasha loves Tomas is that the sex is great.

And there is Artie. He rides a motorcycle, has incredibly skinny legs and looks like James Dean, “except for the acne scars that pit his face.” He always has a copy of “The Great Gatsby” in his pocket. “One day I will memorize it,” he says. “One day I would like to have shirts in every color, and I would really like to know how you go about fixing the World Series. I know people who would pay big money for that kind of intelligence.” He sees himself as a “businessman” in the grand Mafia tradition. He’s really just a two-bit hustler.

And there is Concepcion. The widow of the General, she is Tomas’ grandmother. When she was 16 and living on her parents’ farm in Mexico, a group of ragtag soldiers rolled through, led by the General riding a white horse. (The General always rode a white horse into battle, thus El Caballo Blanco). Concepcion remembers thinking, upon first seeing the General, that “this man will be famous one day,” and she jumped on the white horse behind him and never saw her family again.

Unlike most warriors, the General depended completely on Concepcion. He trusted her intelligence, her emotions, and she went into every battle with him and his men. Twice she walked through the inspection line and pointed to the soldier who had been sent to assassinate him. Explains Concepcion, “Part of the reason I was a perfect wife for the General, is that I . . . appreciate the fullness of life in each moment.” Concepcion sees herself as the grand puppeteer pulling all the strings. She’s really an old woman living in the past.

When Tomas was 10, Concepcion brought him to Los Angeles to live with her. She feared for her grandson in Mexico City, where he already had learned how to steal cars, pinch the maids and smoke marijuana. “Without war,” says Concepcion, “men destroy themselves in wanton ways. Men seek their own destructions if there are not other men with guns and politics trying to kill them.”

Alas there are no more wars for Tomas to fight, at least the kind of wars Concepcion talks about, and Tomas settles into running the restaurant and making the odd drug deal.

But Concepcion has filled Tomas’ head with stories of the General’s heroic adventures and that he, unlike others, has the blood of warriors running through his veins, and he and Artie get involved in a gem heist--and in way over their heads.

Paul, a blond, rich kid from Newport Beach, who frequents the El Caballo Blanco, makes Artie and Tomas an offer they can’t refuse. Paul’s father, who is a State Department honcho and wants to retire in style “so he can afford a house on the 18th hole of the country club of his choice,” plans to smuggle rubies out of Burma and needs someone to unload them.

There is the inevitable screw up, the drama at customs at LAX, the imagined betrayal, the obligatory high-speed car chase and the denouement in a dark alley.

The problem is that after all this drama, the only thing that seems to have been affected, is El Caballo Blanco--it has a new stove. Sasha is still a waitress posing as an actress. Tomas still runs the restaurant. We know that Artie will never memorize “The Great Gatsby,” let alone know anyone who will pay big money for anything. And Concepcion settles back into telling stories about the General.

Smoodin (“Urus Major,” “Presto,” “Inventing Ivanov”) has been described as a “quirky” writer. I think that’s right. “White Horse Cafe” is a quirky book. It’s not bad. It’s just that it’s not very good. Smoodin’s characters and her vision of Los Angeles are so laid back that “The White Horse Cafe” remains virtually passionless.