Daisy Shoemaker can't sleep. With a thriving cooking business, full schedule of volunteer work, and a beautiful home in the Philadelphia suburbs, she should be content. But her teenage daughter can be a handful, her husband can be distant, her work can feel trivial, and she has lots of acquaintances, but no real friends. Still, Daisy knows she's got it good. So why is she up all night? While Daisy tries to identify the root of her dissatisfaction, she's also receiving misdirected emails meant for a woman named Diana Starling, whose email address is just one punctuation mark away from her own. While Daisy's driving carpools, Diana is chairing meetings. While Daisy's making dinner, Diana's making plans to reorganize corporations. Diana's glamorous, sophisticated, single-lady life is miles away from Daisy's simpler existence. When an apology leads to an invitation, the two women meet and become friends. But, as they get closer, we learn that their connection was not completely accidental. Who is this other woman, and what does she want with Daisy?