The brutal execution of an innocent man. The undercover DEA agent who fooled the Hells Angels in a 400kg cocaine plot. The brutal execution of a not-so innocent man. The never-ending quest to bring down New Zealand's most wanted gangsters. These stories go behind the headlines, and delve down into a parallel universe which many do not know even exists: The underworld.

Jared Savage's first book Gangland traced the evolution of the methamphetamine drug trade in New Zealand from the late 1990s to 2020. His second book, Gangster's Paradise, focused on the escalation of organised crime: more drugs, more guns, more money. Underworld follows that pattern; the situation is now even more dangerous. The stakes even higher.