The film takes place after the events of the second installment, where Po (voiced by Jack Black) is struggling to find a new Dragon Warrior. Meanwhile, a new villain, Kai (voiced by J.K. Simmons), a powerful and evil spirit, threatens the Valley of Peace. Po must team up with his long-lost biological father, Li Shan (voiced by Bryan Cranston), and the Furious Five to stop Kai and save the valley.