When the mutilated body of a young woman is left in front of a popular politician’s home, Donovan Montgomery, forensic psychiatrist, profiler, and serial avenger, is drawn into a web of crime and black magic that is bizarre even by her standards.

Donovan prefers to work alone, but the Chicago PD homicide chief has her harnessed on this case with Beau Hadley, a young detective fresh from Wyoming. Donovan chafes at having to work with a partner but soon finds Hadley is the least of her problems. It becomes clear that the location of the body drop was far from random and that Eddy Zunigas, the shadowy figure at the center of the deadly web, is a key figure in an international drug cartel.

Eddy is also a homicidal, fanatical devotee of Santa Muerte, a Mexican folk-saint believed to guide souls from this earthly realm to the afterlife. Eddy’s convinced that Santa Muerte makes him impervious to his enemies and that the greater the blood sacrifice made to the saint, the more invincible he grows.

His enemy has become Donovan Montgomery, and when Eddy threatens those closest to her, the case turns personal. Now triggered, Donovan’s inner demon screams to once again be unleashed to take on this madman. But can it be done without Donovan revealing her own murderous secrets she’s so desperate to hide and protect?