Po's master, Shifu, decides to retire his teachings and promote his Dragon Warrior to become the teacher of the rest of the Furious Five in the ways of kung fu.  His new and somewhat reluctant status as a martial arts master is soon after put to the test when a spirit warrior named Kai thrusts himself into the mortal plane after gathering all of the chi, the Chinese term for the mystical energy that flows within us, he can get from those who have learned to harness it best: the kung fu masters.  Meanwhile, Po is visited by another panda named Li who reveals himself to be his long-lost father, who takes him to a hidden valley where the rest of his panda brethren have been living in relative harmony.  With Po the only entity that can stop Kai's path to total domination, the happy village, and perhaps all of China, rests in the paws of the kung-fu panda.