Invasive species cost the world an estimated €400 billion a year, and the EU now lists 42 animal and 46 plant species as officially invasive. This film follows the people trying to hold the line. Thomas Beissel, a former computer specialist turned beekeeper, has become one of five full-time Asian hornet hunters in his region, tracking the insects with tiny GPS transmitters glued to captured hornets so he can find their nests high in the tree canopy before the hornets wipe out more honeybee colonies. Biologist Annegret Grimm-Seyfarth trains sniffer dogs to locate harder-to-see invaders, from American mink to Japanese knotweed and ragweed, while in Switzerland dog teams are now used to sniff out Japanese beetle larvae before they damage vineyards. The film moves between these fieldwork scenes and brief context on why the Intergovernmental Panel on Climate Change names invasive species among its six major drivers of ecological disruption. It is a grounded look at unglamorous, labor-intensive conservation work rather than a broad ecological survey.