Winter 1925 in Alaska. Nome, a small place situated almost at the north pole, is cut off from the external world. But the children and their friends, the clumsy polar bear, the clever seal and of course the huskies keep on playing anyhow. But then one child after another gets sick. "Diphtheria ", says the doctor, " we don't have enough medicine." There is only one chance to save the children. Balto and Kemo, the two fastest sled dogs of the village are chosen to get the medicine from the city. But this City is more than 400 miles away from Nome.
