Mariana embeds with crypto scammers who show her how they make millions.

Mariana investigates the mysterious next wave of America's opioid crisis.

Mariana van Zeller tackles the black market for tigers and tiger parts, so secretive and dangerous that few have attempted to uncover its ugly details.

Mariana investigates how illicit oil is fueling terrorist groups worldwide.

Mariana investigates the growing influence of heavily armed militias.

Mariana heads to a Southeast Asian hotbed for scamming, where criminal organizations are holding thousands of hostages and forcing them to scam.

Mariana explores surrogacy's dark side; a babies-for-cash black market.

Mariana explores the growing influence of Mexican cartels in the U.S.

Mariana investigates the deadly world of illegal street racing.

Mariana investigates a new breed of cocaine trafficker: lady bosses.

An alarming message from her son's middle school about MDMA sparks van Zeller into high gear. She traces the supply chain of "the love drug" within the Los Angeles clubs back to its booming epicenter in the Netherlands, where a mob-infested underworld has recently murdered a well-known journalist.

Mariana investigates the lucrative black market for private data.

Mariana investigates the underground market for shark fins.

Mariana investigates the global phenomenon of armored car heists, responsible for some of the most brazen and dangerous robberies in the world

Mariana investigates the global surge in anti-LGBTQ+ violence.

Mariana sets out to understand the ugly business of illicit sex in America.

Mariana exposes the dangers of the growing and deadly ghost guns industry.

Mariana investigates the dark underworld of fraudulent addiction treatment programs.

Mariana tracks a smuggling route of stolen cars from the U.S. to West Africa.

A look at the complex inner-workings of the global underworld, black and informal markets.

Mariana meets the craftsmen who make and sell the world's finest counterfeit U.S. dollars.

Mariana attempts to understand the vanity, insecurity and greed that drives steroid use.

Mariana van Zeller investigates underground plastic surgery, from motel-room operations to a deadly revelation about Miami’s discount surgery centers.

Mariana meets the villains behind an exploding online romance scam.