The Cross sisters have lived their entire lives on the sprawling grounds of Mercy Hill, the embattled Raleigh mental hospital run by their formidable mother. Since childhood, JJ, Caro, Mimi and Denise have been inoculcated with their mother's mission: they'll work alongside her to protect Mercy Hill from the fate of other state hospitals across the country, which are being gutted and closed, one by one. After an incident involving the highest-security ward, Mercy Hill faces greater scrutiny than ever, and Lisa Cross pushes each of her daughters even harder in the name of her mission. As the sisters cross into adulthood, the pressures of their isolated environment and mercurial mother set them on different --- and perilous --- paths. And as the battle wages on, youngest sister and narrator Denise grapples with the added responsibility that comes from being the last hope for their mother’s dreams.