The film tells of the beginnings of the Serengeti National Park in Tanzania. At the end of the 1950s, the Tanzanian National Park Administration wanted to fence in the protected area around the Ngorongoro Crater. Bernhard and Michael Grzimek were invited by the national park administration in 1957 to get a precise picture of the animal migrations and to provide the national park administration with the values they needed for their project. Using a new counting method with two airplanes, the Grzimeks found out that the migration of the herds was different than assumed.