Laura Ling travels to the border towns of Juarez and Tijuana, Mexico where drugs gangs are fighting for control of the drug routes into the United States. Ling also goes to the city of Culiacan in Sinaloa State, a region that’s known as the birthplace of narco-trafficking in Mexico. Despite the 40,000 federal troops that are patrolling cities across Mexico, violence is increasing and the methods of killings are becoming even more brazen and grotesque. Ling speaks with gun dealers in El Paso, Texas and U.S. officials about the illegal smuggling of weapons into Mexico–90% of the weapons seized in Mexico have been traced back to the U.S. She examines the culture of corruption and lack of public trust in a police force that has become known for working with the cartels.