Horror movies don’t usually disturb Flora Collins. But after she watched Jordan Peele’s Us—the 2019 thriller in which all humans have doubles living underground, waiting to escape and slaughter their aboveground twin—she left the theater feeling “discombobulated.”

A few hours later, on the street in Manhattan, a woman approached her claiming they knew each other. Collins was sure she had never seen this woman’s face before, but the woman insisted. “I felt like I was in an alternate dimension or something,” Collins tells me from her apartment in Brooklyn Heights. She later discovered that the woman was the mother of a former pre-school classmate—someone she hadn’t seen in 25 years, since she was three years old.

This incident, and the lingering feeling of “not knowing exactly what’s going on in your reality,” became the inspiration for her first novel, Nanny Dearest, to be published next week.

The novel starts with a similar run-in. Walking in Manhattan, Suzy Keller, the very depressed 25-year-old protagonist whose father’s recent death leaves her orphaned, is stopped by a thin, middle-aged woman who insists she was her childhood nanny. Despite her initial skepticism, Suzy slowly starts to remember Anneliese. They spend a few hours, then days, then weeks, together, as Suzy grieves her dad and tries to remember her repressed childhood.

“This is going to sound very Freudian of me,” Collins says, “but I am very interested in how childhood affects who we are as we grow up.” As an infant, Collins, too, had a nanny she barely remembers, a woman who turned out to be “a pathological liar” and, later, the subject of much family lore.

Collins, who is 28, was raised in Manhattan with a writer as a mother, the fashion journalist Amy Fine Collins. At six years old, instead of telling adults she wanted to be an actress or a princess, Flora Collins told them she wanted to be a novelist, and she wrote short stories throughout her 13 years at an all-girls school.

“I am very interested in how childhood affects who we are as we grow up.”

Girls are the focus of Nanny Dearest—mothers, substitute mothers, daughters, best friends—and the novel’s chapters alternate between the present day, narrated by Suzy, and the mid-90s, narrated by Anneliese. “I do not like writing from the same perspective for 300 pages,” Collins says. Plus, the two timelines let Anneliese detail the year of babysitting—one that Suzy can’t remember starting or ending—without spoiling the mysterious reasons she left and then returned.

When Collins started writing the novel, in the spring of 2019, she wasn’t sure why Anneliese returned, either. Collins doesn’t outline. Instead, she starts with a premise, characters (someone grieving, someone else unraveling), and a mood (inspired by horror films and true-crime documentaries). The plot comes as she writes.

“I read a lot of books about unstable women,” Collins says, “and I also watched a lot of documentaries and movies about crime and people who go mentally awry.” Unlike the schlocky true-crime documentaries she loves—with stilted re-enactments and voice-overs by baritones—Collins wanted to look inside the brain of a woman who has snapped. “I like thinking about the perspectives in these crimes that aren’t spoken about as much.”

Collins isn’t finished with the subject. Two months before her first novel went on sale, she had already finished a draft of her second—another stand-alone thriller.

Flora Collins’s Nanny Dearest will be published on November 30

Jensen Davis is an Associate Editor for AIR MAIL