As smugglers attempt to sneak drugs across the Caribbean, U.S. law enforcement agencies work to intercept the shipments before they reach land.

Across cities and farms, meth addiction grips the state of Indiana, overwhelming cops and forcing countless residents to seek "refuge in oblivion."

In America's Motor City, dealers cut corners to sell molly to the masses while police officers try to "think like the bad guys."

Camera crews examine fentanyl's impact on addicts and how overwhelmed customs agents are striving to stop the flow. Also, a Boston dealer talks money.

A large shipment of cocaine is transported from rural Colombia to bustling Madrid. Smugglers beware: Police may be waiting to pounce.

As dealers and smugglers take advantage of addiction in Los Angeles, law enforcement agents search for drugs on both land and sea.

In the port city of Rotterdam in the Netherlands, cocaine kingpins employ fearsome hitmen to intimidate and silence suspected informers.