Hot on the trail of Mexican smugglers and their human cargo, border patrol agents crash through the underbrush along the Rio Grande River, the total darkness pierced with high-tech electronic night vision. The frenzied chase to secure our national borders escalates nightly.

Policing America's borders: Drugs, guns, cash, exotic animals, even human beings, the flow of contraband into the United States has become a tidal wave. The government spends billions to stop the smugglers and admits it only touches the tip of the iceberg. This episode takes you from the agents on the front lines to the politicians in Washington in search of answers in a battle that many fear we are losing.