Nuclear war has wiped out human civilisation and Caesar (Roddy McDowall) now leads a new agrarian society where primates both human and simian coexist and the word “No” is forbidden. When he ventures to the ruins of the Forbidden City Caesar discovers radiation-scarred human mutants who, fearing an attack by the apes, plan an all-out assault on Ape City—music to the ears of discontented human-hater Aldo (Claude Akins) and his fellow gorillas, itching for a final showdown. Featuring John Huston as the Lawgiver.