In a rough neighborhood of Oakland, the police search for a mysterious RV whose driver may be a major drug distributor. In Baltimore, addicts, dealers and law enforcement officers talk about Baltimore's transformation into the heroin capital of the US. South of the border, drug traffickers pull out all the stops to smuggle large quantities of marijuana into the United States. Cops try to get guns off the streets just before Memorial Day weekend, as drug dealers prepare for a flood of buyers.