FBI Agent Ella Dark has studied serial killers from the time she could read, devastated by the murder of her own father, and has gained an encyclopedic knowledge of murderers. A victim of a new killer is found dead, an ancient water clock mysteriously dripping on her body—and Ella knows she has precious little time to decode this killer’s riddle, and stop him before he finds his next target…

FBI Agent Ella Dark has studied serial killers from the time she could read, devastated by the murder of her own father, and has gained an encyclopedic knowledge of murderers. A victim of a new killer is found dead, an ancient water clock mysteriously dripping on her body—and Ella knows she has precious little time to decode this killer’s riddle, and stop him before he finds his next target…