Follow the officers and agents of U.S. Customs and Border Protection (CBP) as they scour the inhospitable landscape at one of the busiest border crossings in the country, seeking to fight terrorism and intercept illegal entrants from the air, on the ground, and at the ports of entry. S4 E1 Bullets Over the Border S4 E2 Meth Mobile S4 E3 Contraband Corridor S4 E4 Rio Grande Reef...