No other European destination has as many incoming and out-going «flights» as Lake Constance: it's the main hub for migratory birds in Western Europe. Over 300 different species pass through every year: that's more than a quarter of a million birds. Lake Constance is so large that, standing on one shore, the Earth's curvature prevents you seeing the opposite bank. This body of water is large enough to influence the climate, and the soil round about is so fertile it creates its own ecosystem. Red-crested pochards, whooper swans, alpine swifts - and raccoons: the lake is home to a myriad of species. This film explores the secrets above and below the surface and on the banks of this lake which links Austria, Germany and Switzerland with no borders in between.