Each year the US economy is flush with more than $500 billion generated in illegal transactions. From sex, weapons and drugs to gambling and counterfeit merchandise, nothing is off limits and seemingly everything is for sale. In `Underworld, Inc.', National Geographic Channel is granted unprecedented access to this `free' enterprise. Workers, suppliers, sellers, customers - and law enforcement personnel trying to keep it in check - share their experiences of an underground industry that is brutal, exploitive and corrupt.
