How could it happen that the Dutch State became the largest drug importer of the 1990s? The docuseries takes a look at the dark undercover world of the Interregional Criminal Investigation Team (IRT), a specialist police force founded in 1988 to combat organized crime in the Netherlands. This prestigious police team infiltrated the criminal environment, as a result of which it became increasingly involved in drug trafficking, among other things. The delta method, as this infiltration technique is called, led to the police team even having its own drug line from South America to the Netherlands in the 1990s. In 'De IRT Affair', the main characters tell their story about how they imported thousands of kilos of drugs in the period from 1988 to 1993 to combat organized crime.