The story begins in a hospital with detective Emmanuel Ritter and his wife celebrating the birth of their baby son. When Ritter receives a call from his office, he leaves and a nurse takes the baby to the nursery. Another nurse, who took the next shift, locks the nursery door, takes out a scalpel, and starts to stab Ritter's son and other infants in the nursery. Before anyone can break into the nursery, the nurse has killed all the newborns and slit her own throat.
Many years later, Ritter remains traumatized and emotionally distant, unable to process the death of his son. At work, he learns of a mass shooting at an elementary school. This turns out to be only one of a series of gruesome massacres in the area. Ritter embarks on a paranormal investigation, looking for an excommunicated priest and trying to find the evil force responsible for the shocking incidents.
