Wayne Adam Ford walks into the Humboldt County Sheriff's Office in Northern California in 1998 carrying a woman's severed breast in his pocket, then confesses to police because, he says, he cannot stop himself. The 36-year-old is eventually convicted of torturing and murdering four women, and this film reconstructs how investigators built that case using previously sealed testimony and interviews with detectives, prosecutors, and others close to the investigation. Author Caitlin Rother, who wrote the book "Body Parts" about the case, appears as the guide through Ford's history, from a troubled childhood through a string of failed relationships to the escalating violence that ended in murder. The film does not soften the details: Ford cut off his victims' breasts, in at least one case while she was still alive. Rother's account also considers what let the crimes continue as long as they did, pointing to gaps in mental health treatment and the broader pattern of violence against women. The film stays close to the confession itself and the physical evidence that followed it.