Long ago, as the Earth was emerging from the Ice Age, there were three brothers. After a bear takes the life of the oldest brother, impulsive youngest brother Kenai kills the bear in revenge, only to be transformed into a bear himself. Denahi, the middle brother, comes upon this bear and, thinking it killed Kenai, vows revenge. Now brother hunts brother and Kenai’s only hope for survival is to befriend his own worst enemy, a grizzly cub named Koda. Koda’s main goal is to show Kenai the real meaning of brotherhood.