Twenty-four-year-old New York bookseller Naomi Ackerman is desperate to write a novel, but she struggles to find a story to tell. When, after countless disastrous dates, she meets Caleb, she thinks she's finally stumbled onto a time-honored subject: love. Then Caleb's ex-girlfriend, Rosemary, enters the scene. Upon learning that Rosemary is not safely tucked away in Caleb’s homeland overseas, but in fact lives in New York and also works in the literary world, Naomi is threatened and intrigued in equal measure. If they both fell for the same man, what else might they have in common? The more Naomi learns about Rosemary, the more her curiosity consumes her. Before she knows it, her casual Instagram stalking morphs into a friendship under false pretenses --- and becomes the subject of her nascent novel.