This documentary presents an epic portrait of winter bird migration. Filmed on all seven continents over the course of several years, the footage is brought together into one portrait of a journey that is uniformly arduous for all kinds of different birds. These long and often torturous treks are a matter of survival. Along the way, the birds face dangers both large and small, from man-made waste to a group of hungry crabs. The search for food, good weather, and a place to hatch their young takes this annual cycle of stamina across continents and oceans.