Mariana investigates fentanyl, a drug that has contributed to the deadliest narcotics crisis in US history.

Mariana meets the craftsmen who make and sell the world's finest counterfeit dollars in the United States.

Mariana attempts to understand how a person's vanity, insecurity, and greed contribute to their steroid use.

Mariana sets out to understand the ugly business of illicit sex in America, meeting pimps, victims, undercover officers, and private investigators.

Mariana retraces one of the world's most intractable smuggling routes, following cocaine's path around the world, from the Peruvian jungles to the Colombian coastline and to the streets of Miami.