When a young nanny is found dead under mysterious circumstances, new mom Tash is intrigued. She has been searching for a story to launch her career as a freelance journalist. But she also has been searching for new friends to help her navigate motherhood. She sees them at her son’s new playgroup. The other mothers. A group of sleek, sophisticated women. When the mothers welcome her into their circle, Tash discovers the kind of life she has always dreamt of and is quickly swept up into their wealthy world. But when another young woman is found dead, it’s clear there’s much more to the community than meets the eye. Are these women really her friends? Or is there another, more dangerous reason that she has been so quickly accepted into their exclusive world?

Helen’s idyllic life begins to change the day she attends her first prenatal class and meets Rachel, an unpredictable single mother-to-be. Rachel doesn’t seem very maternal, but Helen is still drawn to her. She makes Helen laugh, invites her confidences and distracts her from her fears. But her increasingly erratic behavior is unsettling. And Helen is not the only one who’s noticed. Her friends and family begin to suspect that her strange new friend may be linked to their shared history in unexpected ways. When Rachel threatens to expose a past crime that could destroy all of their lives, it becomes clear that there are more than a few secrets laying beneath the broad-leaved trees and warm lamplight of Greenwich Park.