In 2005, seven European countries signed the so-called Prüm Treaty to increase transnational collaboration in combating international crime, terrorism and illegal immigration. Three years later, the Treaty was adopted into EU law. EU member countries were now obliged to have systems in place to allow authorities of other member states access to nationally held data on DNA, fingerprints, and vehicles by August 2011. In this paper, we discuss the conditions of possibility for the Prüm network to emerge, and argue that (...) rather than a linear ascent towards technological and political convergence and harmonisation, the story of Prüm is heterogeneous and halting. This is reflected also in the early stages of implementing the Prüm Decision which has proven to be more challenging than it was hoped by the drivers of the Prüm process. In this sense, the Prüm network sits uncomfortably with success stories of forensic science . Instead of telling a story of heroic science, the story of Prüm articulates the European dream: one in which goods, services, and people live and travel freely and securely. (shrink)