Season 6

The border between the US and Mexico is the busiest in the world. This season, follow the work of America's Customs and Border Protection Agency as officers seize record amounts of illegal drugs entering the country from the south. They're also trying to halt the relentless flow of laundered cash, military-grade firearms and ammunition across the border because the cartels rely on it to fund their continuing power struggle in Mexico's border towns along the mighty Rio Grande.