Every spring, a unique migration takes place in the Bavarian Alps. More than ten thousand common toads embark on an adventurous journey, risking life and limb to reproduce. Their destination: three crystal-clear lakes in what appears to be an idyllic valley. To reach it, the amphibians must surmount steep rock faces and cross a busy mountain road. And once they arrive, they are faced with predators hoping to feast on them and their future offspring, which depends on the lakes to mature.