Part of the NATURE series on PBS, this program shares the intensity, precision teamwork and emotional nuances of the 1,200-mile Iditarod race through the Alaskan wilderness. The annual event, which grew out of a celebrated medical rescue mission by sled dogs early in this century, honors the heroic traditions of sled dogs in northern settlements. Focusing on the mutual dependence of human and animal, the program underscores the extraordinary degree to which each relies on the strength and spirit of the other to overcome the harsh environment. (60 minutes)