After conquering the oppressive humans in "Conquest for the Planet of the Apes", Caesar must now keep the peace among the humans and apes. Gorilla General Aldo views things differently, and tries to cause an ape civil war. In the meantime, other human survivors learn of the ape city, and decide they want to take back civilization for themselves, thus setting the stage of warring ape factions and humans.
 
http://www.imdb.com/title/tt0069768/