Ostrich-sized rheas trample fresh shoots in the farmlands of northern Germany. Flocks of bright green parakeets screech around Cologne cathedral. And beaver-like, orange-toothed coypus gnaw at Dutch dams and dikes. All these “nuisance” animals are non-native and are suspected of causing ecological and economic damage. Should the invaders be fought against? Or is it just prejudice against previously unknown species? This short series of three films gets to the bottom of the accusations against alien species. To achieve this, the immigrant creatures are observed in their new environment, their relationship with other species is examined and the latest scientific findings are presented.