In The Nest, Cynthia D’Aprix Sweeney’s glorious New York novel, four adult siblings meet at the Grand Central Oyster Bar & Restaurant for some fresh coffee and old roles.

“The three of them wondered how he did it, how he always managed to be unruffled while putting everyone else on edge, how even in this moment, at this lunch, where Leo should be abashed, laid bare, and the balance of power could have, should have, shifted against him, he still commanded their focus and exuded strength,” Sweeney writes. “Even now, they were deferentially waiting, hoping, he would speak first.”

Leo Plumb, 46, is the fortunate son with the TriBeCa loft, a new media mogul who cashed out to join the jet set. As the oldest, he’s set the lifelong pace for his younger siblings: Jack, 44, a gay antiques dealer in the West Village, was frustratingly known, in adolescence, as “Leo Lite.” Bea, 42, a widowed writer on the Upper West Side, owes the early success of her career, in part, to Leo’s inspiration and connections. And even though Melody, 39, has a husband, children, and a mortgage on a suburban house 30 miles north, she defers to her big brother when it comes to solving family problems.

“The book is very much about the thing that everyone inherits, which is a place in a family narrative,” Sweeney says. “You’re born into a story that you have no control over, including who the other characters are, and I think the reason I’m so fascinated with adult siblings is because everyone—to different degrees, but at some point in their lives—has to figure out how to reconcile the story you have inherited with the one you are writing for yourself.”

The Plumbs’ problem du jour is entirely Leo’s doing, and it’s a doozy: an inebriated indiscretion at a cousin’s Long Island wedding resulting in an injurious accident, a stint at a top-shelf rehab facility, and hush money paid to a bright-eyed cater waitress and a merciless soon-to-be-ex-wife. To cover these significant expenses, their otherwise disengaged mother drains the heretofore inviolable family trust, nicknamed “The Nest.” The account was devised by their shrewd father, the late Leonard Sr., to give them all a bump in middle age.

“Keeping the money tied up until Melody was forty appealed to Leonard for many reasons,” Sweeney writes. “He was realistic about the maturity—emotional and otherwise—of his four children: not commendable. He suspected if they didn’t get the money all at once, it would become a source of conflict between those who had it and those who didn’t; they wouldn’t be kind to one another. And if anyone was going to need the money earlier in life, Leonard imagined it would be Melody. She wasn’t the brightest of the four (that would be Bea), or the most charming (Leo), or the most resourceful (Jack).”

The Oyster Bar meeting is called to determine when—or if—Leo intends to pay back the $2 million owed The Nest (or the $1.5 million, minus his share). If it’s not replenished soon, middle age may get bumpier for Jack, Bea, and Melody, who’ve all made decisions based on its eventual disbursement.

“It’s an East Coast story, in terms of the family wealth and this sense of our family has money we are going to preserve in some way,” says Sweeney, a native New Yorker living in Los Angeles. “That sense of expecting certain things and feeling trapped by not wanting to lose them or move or backtrack in any way is very, very New York. And it’s about people who are clinging to their place in New York, in that way that’s particular to New York. People are not as invested in where you live in Los Angeles, almost everyone’s from somewhere else, and their love and nostalgia for Los Angeles is not quite as white-knuckled as being a New Yorker is—it’s a huge part of my identity and a big part of this book.”

The Nest’s sharp New York satire speaks to a keen ear and insider’s eye. The other mothers at Melody’s twins’ school, “look at each other and shrug and say, ‘luxury problems,’ cackling like some modern skinny-jean-wearing equivalent of Marie Antoinette’s court,” she writes. On Bea’s grouchy downstairs neighbor: “Did he even sleep? Or did he just sit, alert, clutching his broomstick, waiting for her auditory trespasses.” And her writer nemesis: “Bea couldn’t believe how regal Lena sounded, as if someone had appointed her the fucking Emperor of Fiction.” With riotous results, Sweeney takes on old money, new money, publishing, digital media, real estate, education, and the collisions that come from living in a city of 8.4 million strangers, neighbors, friends, and foes.

A colorful array of supporting characters feathers The Nest, beginning with Matilda Rodriguez, the Long Island waitress (with Mariah Carey aspirations) who takes a ride with Leo. There’s Stephanie Palmer, Bea’s former literary agent and Leo’s former flame; Paul Underwood, the forthright publisher of a small literary magazine, Paper Fibres; Cpl. Vinnie Massaro, a young Italian-American war-wounded veteran; Tommy O’Toole, a 9/11 widower and former firefighter in search of a sign; Jack’s husband, Walker; Melody’s husband, Walter, and their college-ready twin daughters, Nora and Louisa—and many more to meet.

“It’s an ensemble piece,” Sweeney says. “That was important to me when I was writing it, and there were a few times along the way when I had to make an argument for why it should stay that way. Turning down the volume on the peripheral characters, and really concentrating on a book about four siblings fighting over their inheritance, to me, is not as interesting a New York book. There are other people in New York who deserve [attention].”

Somebody tell that to Leo Plumb as he weighs how—and whether—to pay back his embattled siblings. Anyone wondering what tack he’ll take might do well to analyze his favorite expression: “If you want to predict a person’s behavior, identify his or her incentives,” she writes.

As a debut novelist, Sweeney’s incentives are straightforward: tell a great story that entertains readers as well as herself.

“I want to create a world that feels real, that you can live in as a reader, that you want to keep going back to,” Sweeney says. “I worried about [The Nest] feeling both emotionally authentic and authentic in terms of place, but I also wanted it to be entertaining. It’s lonely sitting in your office all day writing things, so if you’re not having fun—and fun is different for all different kinds of people, of course; Knausgaard’s idea of fun while he’s writing is probably different from mine—you can write something that is emotionally very tough or you can write something that challenges you from a craft standpoint, but, at the end of the day, it’s a pretty odd way to choose to spend your time if it doesn’t please you.”