When a young bus driver approaches the border without any passengers in his coach, officers suspect a smuggling operation may be underway; a man attempts to drive into the U.S. with a van full of goods loaded with more than just clothing.

Officers find a man and his family driving a suspiciously modified truck. A young man is caught with narcotics strapped to his body. A crosser is detained for having a record of smuggling an illegal migrant across the border.

A speaker cabinet is found to be carrying more than just sweet beats. A driver who took a wrong turn and ended up at the border crossing is packing more than he should be. Following a recent smuggling trend, officers carry out a special operation.

When a lone driver avoids answering officers' questions, an X-ray reveals dark shadows along her car's floorboard, a sign she could be smuggling narcotics; a semi-pro boxer is detained after being flagged for having a warrant for his arrest.

When an X-ray reveals strange shapes inside a car's spare tire, the officers' investigation doesn't turn up flat. A group of unofficial couriers known as Paqueteros attempts to cross the border with something a little extra in their load.

After a K9 alerts to a vehicle, officers have trouble finding anything, but eventually a secret compartment reveals its contents. Officers question a man who claims he's driving his friend's truck across country because his buddy needed to eat dinner.

When hidden among shipments of narcotics and firearms worth billions, even the most innocent-looking contraband -- like a simple snack or sweet treat -- can be more than what it seems.

While some officers wear a badge, others wear a leash. Over a thousand highly-trained K9s are on the scent, and if something's hidden, they'll find it -- because at the border, man's best friend is a smuggler's worst nightmare.

Officers process thousands of families crossing the border every day. Some carry memories, while others carry contraband. Because sometimes, families who travel together ... smuggle together.