The Last Orange Grove : POMONA QUEEN, <i> By Kem Nunn (Pocket Books: $19; 211 pp.)</i>

Kem Nunn does for Pomona what Raymond Chandler, James M. Cain and Nathanael West did for Los Angeles. He depicts the squalid underbelly of a soiled landscape, a legacy of decay inhabited by foul-mouthed lowlifes and scumbags.

In his third novel, “Pomona Queen,” all the action transpires in one very long night. It opens with Earl Dean, heir to the last acre of orange grove in Pomona, hawking Rainbow Air Purifiers--a fancy name for vacuum cleaners--door-to-door in a rundown tract of cheap look-alike houses with unkempt yards. Dean is lost in a part of town he doesn’t like. It has no sidewalks or street lights, and the addresses are illegible. But he dutifully makes one more call.

This last stop turns out to be the residence of Dan Brown, a burly, beer-bellied biker he knew 20 years ago in high school when Dean played piano and sang with his own band, using the moniker Johnny Magic.

Brown, a violent boozer who once beat a cop to death and spent time in prison for stabbing a security guard in the throat with a screwdriver, remembers Johnny Magic’s singing with a perverse fondness.

It just so happens that this unexpected reunion occurs on the night Brown’s brother, Buddy, has been knifed to death. Buddy’s naked body lays stretched out upon a bed of ice cubes in a large red Coca-Cola freezer with white script on the side that reads: “Things Go Better With Coke.” This is the kind of depraved humor that punctuates Nunn’s darkly poetic prose.

Brown plots revenge for his brother’s murder and wants Johnny Magic to sing at the burial. Not keen on being a part of this scene, Dean attempts to escape. He fails. Trapped in a dirty house with Brown, his biker buddies and their old ladies who are ripped on speed, the long night turns into a journey that leads to the past.

Dean’s great-grandfather was a pioneer fruit grower who was mysteriously shot to death in Chinatown. Gramps, the first president of the Pomona Fruit Exchange, had commissioned artwork from a lithographer to distinguish his produce from that of his neighbors; his packing-crate label bore the image of a sad, dark-eyed girl and a crimson sky. Above her head, in gold letters, were the words Pomona Queen.

Pomona Queen is coincidentally also the name of the gang to which Buddy’s killer, a woman, belongs. In the course of the night, Dan Brown’s crowd load Buddy, in his makeshift coffin, into the back of Brown’s panel truck, and the group goes out in search of the murderer.

Dean unwillingly accompanies Brown in a night of unexpected events. To ease the tension, Dean relates stories about his grandfather and the days when the Pomona Valley was the hub of a booming citrus industry. This allows Nunn to weave Pomona’s history into his saga and comment on the changing area that now reeks of smog, trashy used-car lots, overdevelopment and lost promise.

Each chapter begins with an italicized paragraph from a Frank P. Brackett, who in 1920 wrote a “History of Pomona Valley.” These snippets add very little to the novel’s narrative and tend to slow it down, but Nunn’s own description of Pomona’s decline is compelling. In the downtown district, shoppers disappeared and were replaced by the winos who lined up to buy booze from Thrifty’s drugstore. Graffiti began to appear on storefronts and businesses began to fold, Nunn writes, “and that had pretty much been it for the town. One more broken promise. One more plan gone sour. The land would only stand so many. One could look back on it now, all those folks with their big plans. . . . One could speculate, with the advantage of hindsight, upon the causes of it all. In fact, if one were so inclined, one could find evidence of the virus on every hand--the power virus as real-estate bug, the insatiable self as the death seed, the shadow at the base of the skull. . . . There was an equation somewhere.”

What follows is a night of boozing with a bartender called the Stench, mayhem that includes car theft and losing Buddy’s body, and an adventure filled with endless terror. Nunn displays an impressive knowledge of the ecological factors that have warped a once pristine prairie. His flair for language and explicit vision put him among the disaffected who warn of an environmental apocalypse.