By Gigi Levangie Grazer. Simon & Schuster. 359 pp. $24

Gracie Pollock should have suspected that her movie executive husband, Kenny, was cheating on her when he began to wear the earring. But she missed the clues, and at the age of 41 -- which makes her, as a Hollywood woman, almost assisted-living-ready -- Kenny dumps her via cell phone, weeks before their pre-nup would have expired. The heroine of Gigi Levangie Grazer's third novel, The Starter Wife, thus plummets from being a classic Wife Of, botoxed and boob-jobbed -- "easy on the eyes and hard on the 401(k)" -- to being a single mother confronting survival without resources. Well, not quite without resources: She and her 4-year-old-daughter are invited to housesit another Wife Of's glam Malibu digs. So she has a reprieve during which to become reacquainted with her true self and, with luck, snare another man.

"Could a woman over a certain age in Los Angeles be able to find a (reasonable) date?" No reader of this good-natured, fluffy novel will doubt for an instant that she can. Grazer, herself the wife of a Hollywood producer, wrote the screenplay for the feel-good tearjerker "Stepmom," and Starter Wife is the same kind of gentle cultural commentary. It is a world where children behave like children in movies, lobbing winsome, kids-say-the-darnedest-things lines but never causing too much trouble; where money never poses much of an issue in divorce because all the available abodes are as lavish as movie sets; and where single mothers over a certain age look like Susan Sarandon -- and if such women can't get dates, they might as well just drop dead.

Before her life as a Hollywood wife, Gracie had an identity of her own as a successful children's book writer (nothing so threatening as a satirical novelist). As well as having quite nice feet, Gracie is supposed to be observant, with a sharp wit. This Hollywood wife can actually identify lines from Shakespeare. (Okay, she can't tell "Hamlet" from "Macbeth," but we must remember that this is L.A; Gracie's brains, on a 1-to-10 scale, may be "about a seven" in the world at large, but "on the west side of L.A. she was pushing a nine, nine and a half, easy." ) The novel's setup promises that Gracie will serve as "the Jane Goodall of the Beach-Bimbos-and-Bentleys set," skewering Hollywood pretensions. The most enjoyable sections of The Starter Wife do exactly that:

"The demands of a life filled with petty concerns -- Why are the tennis court lights on at eight a.m.? The air-conditioning went above 72 degrees in the guesthouse sitting room! We need new flower arrangements twice a week. Why won't the remote (that cost as much as a new Toyota) turn off the Flat Screen TV in the bar? What is the proper ratio of studio to talent for a dinner party? The orchids in the foyer are dying. Should we serve lamb or salmon at our third dinner party this month? I want a phone on the left side of the master toilet. Who has (imaginary) food allergies? The pool is overflowing. Who doesn't eat meat? That painting doesn't work with the new couch. Who doesn't eat bread? I need another iPod (pre-programmed with Julia Roberts's favorites). The gardener cut the grass too low. The made-in-Tibet screening-room curtains won't open -- had devoured not only Gracie's creativity but, more important, her spirit."

Grazer clearly knows this scene, and is a lively, wry reporter of Hollywood's strident triviality and narcissism. But the novel falters, as many screenplays do, after the setup. The plot twist involving Kenny's new girlfriend, Britney Spears, is flat-out unfunny and reveals the problem with mixing fictional and real characters in a Hollywood novel. Spears feels like an old joke here. Another novelist of Hollywood, Bruce Wagner, has more success using only invented characters as protagonists; he manages to make them even more outre and bizarre than their real-life models.

When Gracie meets her love interest, The Starter Wife leaves comedy behind for romance-novel territory. Gracie and Sam Knight (allusion to Jane Austen's Knightley?) meet cute, when he rescues her from a kayaking accident. He is manly yet sensitive. He is a great kisser. He is also homeless -- but no reader will doubt that he'll turn out to be the prince in pauper's clothing who will not only love Gracie for her spunk, but also allow her to stay in Malibu, entertaining in style her loyal friends (a trio that includes the prerequisite straight-talking, gay interior decorator).

"It's a Malibu fairy tale," Gracie sighs. Indeed. At least the Hollywood version -- real fairy tales, as any reader of the Grimms knows, tend to be a lot nastier and more grisly. *

Lisa Zeidner's most recent novel is "Layover." She is a professor at Rutgers University.