In this thrilling debut for fans of Karin Slaughter and Riley Sager, a social worker turned true-crime podcaster investigates a decades-old serial killer cold case-only to unwittingly create new victims. Former social worker Elle Castillo is the host of a popular podcast that tackles cold cases of missing children in her hometown. After four seasons of successful investigations, Elle decides to tackle her white whale: the Countdown Killer, or TCK. Twenty years ago, TCK established a pattern of taking and ritualistically murdering girls, each a year younger than the last. No one's ever known why-why he stopped abruptly with his eleven-year-old victim, or why he followed the ritual at all. Weeks into her new season, Elle sets out to interview a listener promising a tip, only to discover his dead body. When a child is abducted days later, in a pattern that looks very familiar, Elle is convinced TCK is back. Will she be able to get law enforcement on her side and stop TCK before it's too late?