Nearly a third of all birds in the United States have vanished since 1970, close to three billion animals, while Europe has lost around a quarter of its bird population over the same span. This film tracks the scientists and conservationists trying to understand why, and what makes birds able to survive at all in a rapidly changing world. Cameras follow migratory species across continents, showing the physical feats behind flight, navigation, and the ability to sense magnetic fields, alongside interviews with researchers explaining how habitat loss and climate change are eroding these advantages. Field footage captures nesting sites, wetlands, and forests under pressure from agriculture and urban expansion, while biologists describe specific adaptations, from hollow bones to extraordinary long-distance endurance, that once made birds so resilient. The documentary balances wonder at these abilities with the blunt statistics of decline, making the case that conservation efforts now matter more than ever. It closes on the scientists working to reverse the trend, with no guarantee they will succeed before more species disappear.