A psychotic killer is on the loose. His victims are exclusively women, and each murder is committed twelve-hours from the last. While the police struggle to pinpoint the next target and take down the killer before he strikes again, the F.B.I. has sent in a walking taboo to assist with the hunt. In a world scarred by the aftermath of thinking-machines that suddenly turned on their creators, the federal agent sent to help crack the case is a new Ai unit that will test the detectives on the job and their willingness to look past the bias formed from the incident years ago. Will the killer who leaves his victims covered in satanic symbols be apprehended before twelve hours have run up, or will another woman lose her life to the elusive serial killer?