Underworld, Inc. - Episode Guide

To get away with a crime, criminals look for completely untraceable guns. Enter the "ghost" gun: an exact replica with a fake serial number and no ballistic record--a gun that is potentially invisible to law enforcement.

The illegal, multibillion-dollar global sex trade includes brothels, massage parlors and online escort agencies and is one of the oldest professions. Take a look inside this illegal trade where pimps treat women as commodities — bought and sold, used and abused, then discarded.

Mexican cartels dominate an extremely lucrative industry exporting undocumented migrants and squeezing them for cash. Thousands of Central Americans head north to the US border, lured by hopes for a brighter future, but people smugglers, who are often linked to cartels, make it difficult to cross without their supervision, and for a price.

Millions of Americans love to gamble, but some forms of gambling are restricted or illegal, pushing them underground, where the rules are very different. Here, if you want to play you have to pay.

Anything and everything can be faked: watches, purses, shoes, electronics, smartphones. Go underground to see the breathtaking enterprise and expertise of counterfeiting — an economy that turns over an estimated $500 billion a year.

Go inside the underground economy of knockoff pharma, where the demand for fake drugs continues to grow and buyers can find an abundance on the Internet, in the pharmacies and on the streets.

Being high-proof, low-cost, untaxed and illegal has made the black market for moonshine a big business; urban bootleggers bring in fresh competition and the law is cracking down.

Increased automobile security means that car criminals are becoming more ingenious than ever. Gangs are working together to steal cars — for them car theft can be more profitable than selling drugs.

While 14 people die each day waiting for a kidney transplant, the black market organ trade is thriving; gangsters with global reach pocket easy money in an illegal trade driven by desperation.

US authorities are closing in on cartel cash. If drug lords want their narco cheddar cleaned and moved into the banking system, they have to get it to Mexico. Working to stem the tide, the cops tail cars suspected of smuggling millions.

An oil fracking boom and subsequent bust have brought extortion, prostitution, drug dealing and theft to the remote prairie town of Williston, North Dakota.

From card cheats, to armed robbers, to 'trick' rollers, criminals across America make a beeline for the casinos of Las Vegas.

Fuelled by the huge demand for luxury goods, where customers buy with no questions asked, cargo thieves stop at nothing to get their product into the black market.

Pirates in the South China Sea won't back down in their search for black gold, the world's most precious commodity.

Exploring real world hustlers that take control over supply and demand in the underworld economy, from illegal guns to human trafficking.

The sex trade is a multi-billion-dollar industry in the United States. From working girls to sex industry bosses, everyone's looking for their cut.