This unputdownable book weaves together two stories: the story of a courageous mother, and the story of the rise of drug cartels and of violence in Mexico. The story begins on an international bridge between Mexico and the U.S. Miriam Rodriguez is stalking one of the men who murdered her daughter. He is a member of the Zeta drug cartel that now controls what was once Miriam's quiet hometown of San Fernando, near the U.S. border. Having dyed her hair red and wearing a disguise, Miriam single-handedly orchestrates the arrest of this man, one of the many men she has targeted and gotten arrested for the murder of her daughter, Karen.

Moving back and forth in time, this deeply researched account reveals how the drug cartels built their power in Mexico; how the Zeta cartel took over the quiet town of San Fernando, with its crucial geographic location for drug smuggling, near a crossroads to the US border; and how the cartels, for money, power and control, kidnap and murder victims. Miriam's daughter, Karen, was just one of the many people disappeared by the cartels. Miriam, a brilliant and perseverant woman, begins a vigilante crusade to target Karen's killers, and then to help other victimized families seek justice. Eventually, the success of Miriam's investigation techniques and her activism on behalf of other families lead to her being murdered by the cartel. Then, her son, Luis, finds his mother's briefcase with the names of other targets and her investigation techniques, and quietly continues to pursue justice for his family and for the families of other victims of violence in Mexico.

This suspenseful and shocking story of a remarkable mother who stopped at nothing to seek justice on behalf of her family is also a story of a country, of Mexico, and of the rise of violence, corruption and greed: What happens when a nation slides into unchecked violence, leaving its people to fend for themselves.