Ann Leary hopes she’s not stirring up a hornet’s nest by declaring her fascination with WASPs.

“Are we not supposed to say ‘New England WASPs’?” Leary says. “I hope that’s not derogatory now. ‘People I’ve known who come from old family money’? I’m fascinated by their relationship with money, which is so different from anyone I’ve ever known.”

Leary (The Good House, 2013; Outtakes from a Marriage, 2008), who grew up mainly in the Midwest, resides in a rural Connecticut town teeming with people who come from old family money. Her hilarious and harrowing third novel, The Children, is set in Connecticut and populated by that set.

“If you have a substantial amount of money that you didn’t earn, it seems to be a burden,” she says. “They feel very responsible for it, and they don’t want to spend it. It’s almost like sex—they don’t want to talk about it. They almost don’t want to touch it with their hands. It was dirty. Also, they were obsessed with it.”

Blue-blood Richard “Whit” Whitman eschewed suit and tie to pursue three midlife passions: American bluegrass music, banjo-building, and Joan Maynard—the woman who would become his second wife. After a messy divorce, Whit welcomed Joan to Lakeside Cottage, the quaintly named 20-room waterfront manse built by his robber-baron forefathers; there, they lived modestly off the Whitman family trust while raising her two daughters, Sally and Charlotte.

“Whit loved telling family stories, their general theme being that Whitmans are gritty and combative, they live long and then die when they’re good and ready—not a moment sooner,” Leary writes. “So it must have come as a shock to him to learn that he had cancer at age sixty-five, though it was anybody’s guess how he reacted, as he kept the diagnosis to himself until just a few months before he died.”

Narrated by Charlotte as an adult, The Children opens after Whit is gone, though his convoluted legacy lives on: Lakeside Cottage has been inherited by Whit’s sons, Perry and Spin, who grew up with their mother (who remarried well), with the stipulation that their stepmother be allowed to continue living there as long as she wishes. At a not-quite-Grey-Gardens level of disrepair, it remains home to both Joan and Charlotte, a professional blogger who suffers from anxiety and agoraphobia.

“Joan says I need to learn to adapt,” Leary writes. “I think she’s wrong. I think my problem is that I’m too adaptable. Have you ever seen a large cat fold itself into a tiny shoe box? Or the way a bat wraps its vast wings around its torso until it’s not bigger than a prune? A grown rat can squeeze through a hole the size of a dime. I’m like that. I’m like a contortionist that way. I must have softer bones than most people. I can deflate myself into the tiniest recesses and be quite comfortable there.”

When Spin, the golden child, arrives at Lakeside with his new fiancée from Idaho, the Maynards must adapt. Laurel Atwood has a tragic past, a formidable social media presence, and a book deal. (She claims to be a great-grandniece of Ernest Hemingway.) Though Charlotte and Sally, a professional New York Symphony violinist, are initially suspicious, the former finds herself charmed by her future stepsister-in-law’s unconventional ways.

“[Laurel] was a good sport,” Leary writes. “I liked her more and more. We’re uptight. How was she supposed to know that we don’t run around hugging people or asking about who pays for what? It must have been hard for her to feel at home with us. People are much more easygoing out west, everybody knows that.”

As Laurel swings by with increasing frequency—ostensibly planning for her tasteful onsite nuptials—The Children morphs from comedy of manners into something more sinister.

“I really like to be afraid,” says Leary, who cites the blend of funny and frightening in Shirley Jackson’s fiction as particularly inspiring. “That thing where you’re rollicking along with a book and, suddenly, Oh no!—What happened? Help! No! What?!—I like that. I think it’s kind of how life is. Suddenly the weather changes, one person dies, or a person marries into the family, and everything gets thrown off balance.”

Megan Labrise writes “Field Notes” and features for Kirkus Reviews.