The book 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. Moving back and forth in time, this deeply researched account reveals how the drug cartels built their power in Mexico. 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 to help other victimized families seek justice. 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.