Early on in a novel much concerned with the child-bearing and child-rearing practices of Manhattan's ultra-rich, protagonist Nan Hutchinson falls into conversation with a lawyer who explains to her the "in-vitro offset" in certain prenuptial agreements. Under such a provision, the lawyer says, a divorcing husband who has seen his wife squander a small fortune on fertility treatments "with no output" is entitled to deduct those costs from what he must pay his ex. In other words: No offspring, no full settlement.

For Nan, whom readers and moviegoers will recognize from the best-selling 2002 novel "The Nanny Diaries" and the film starring Scarlett Johansson, this legal gambit is a sign that little has changed since she fled the Upper East Side a dozen years earlier, disgusted by the way the well-to-do put a price on everything and neglect their children in the process. The lawyer's tutorial in "Nanny Returns" also signals that the authors—Emma McLaughlin and Nicola Kraus—are back to what they do best: skewering the manners and mores of those with more money than God.

It starts with appearances. On a drizzly winter day at a Park Avenue lunch party, Nan—now in her early 30s, freshly armed with a graduate degree and trying to launch a business-consulting firm—notices that the middle-age women in attendance look identical. They all have ponytails and wear Anne Fontaine blouses, riding pants and rain boots. How do these women manage to march in such sartorial lockstep? "Is there a blue-blood bat signal that goes up?" Nan wonders. "A dollar-sign silhouette projected against the cloudy sky?"

Their children have their own tribal dress, as Nan learns when she starts consulting at a fancy private school where she has been hired to help the faculty work better with board members. (It's an implausible development, but then plot is not the authors' strong suit.) Boys and girls alike at the Jarndyce Academy favor black separates with pastel shirts and ties. The boys wear long hair that looks "as if they've found their grandmothers' bob wigs and thrown them on backward and slung to the side." Manhattanites will know what she is talking about: Walk down certain stretches of Madison Avenue on any school morning and you'll pass droves of preppy boys flicking hair out of their faces.

Nan tries to hold down her consulting gig and check in with the X boys—she clearly cares about them even though her nanny days are long past—while occasionally rushing back to the brownstone in East Harlem that she shares with her husband, the "Harvard Hottie" from "The Nanny Diaries." Hottie, also known as Ryan, is out of town most of the time working for the United Nations because he is so obviously a good person, which makes him different from just about every other character in the book.

In rare quiet moments at home, Nan stares out of her window at "the Key Food bags that appear to be blooming off the backyard tree" and worries about how the young Xes are going to survive their parents' breakup. Odious Mr. X has left his wife for an actress named Carter Nelson, who reluctantly allows the boys to come live with her in a glass tower in the West Village. But then Stilton burns his hand on the stove—which doesn't look like a stove because Carter has insisted on an artistically rendered kitchen. Nan chooses to take Stilton to the emergency room instead of waiting for the movie star's homeopath to tend to the wound. The indignant Carter announces that New York "may have been ruined" for her by Nan's impudence and decamps for the West Coast, leaving Mr. X and his sons behind.

Meanwhile at the Jarndyce Academy, a handful of students go online to attack their teachers with obscene videos and vicious insults. Some of the offenders are the children of board members, who block the students' expulsion and demand instead the dismissal of the teacher who was the main target of their campaign—and who happens to be one of the school's most effective and compassionate instructors. Nan, appalled, protests but cannot stop the sacking. As "Nanny Returns" moves toward its conclusion, Nan tries her cheerful best to counter the brattiness of the rich, both young and old, while chasing after her own dreams of a flourishing business.

Part of the appeal of "The Nanny Diaries" when it appeared eight years ago was voyeuristic. The authors, who had worked as nannies while they were students at New York University, clearly knew the world they were satirizing. Their underlying message—look how crass and unfeeling the folks at the pinnacle of financial success can be—was welcomed in boom times by those who hadn't made it quite so far. But the theme also has an inherent fascination, and the current financial downturn has not dampened the appeal of Nan's adventures.

Anyone who has read "The Nanny Diaries" will recognize the sequel as much the same in tone and structure. Happily, the detailed observation in "Nanny Returns" feels just as up-to-the-minute—with the earlier book's out-size success, the authors may have been able to do first-hand reporting from the wealthy, nanny-employing side of the equation. In this outing, though, it's apparent that Ms. McLaughlin and Ms. Kraus have thought harder about their material; the result is a novel that is more resonant and less glib than its predecessor.

At a Hamptons house party, the teenage Grayer gets drunk and acts loutishly to a woman about Nan's age. Rather than tell him off, the woman flirts with him. "This is how the Grayers become their fathers," Nan muses. "The women who should be keeping them in check were someone else's neglected daughters and their reflex is to flatter and cajole, no matter what asinine offensive thing trips from the guy's mouth." The cycle continues, even if the recession has dented the trust funds.