Dr. Kate English has it all. Not only is she the heiress to a large fortune; she has a gorgeous husband and daughter, a high-flying career, and a beautiful home anyone would envy. But all that changes the night Kate's mother, Lily, is found dead, brutally murdered in her own home. Heartbroken and distraught, Kate reaches out to her estranged best friend, Blaire Barrington, who rushes to her side for the funeral, where the years of distance between them are forgotten in a moment. That evening, Kate's grief turns to horror when she receives an anonymous text: 'You think you're sad now, just wait. By the time I'm finished with you, you'll wish you had been buried today.' More than ever, Kate needs her old friend's help.