Apes are now pets and servants, but abuse and poor simian conditions provoke Caesar (Roddy McDowall), a highly developed primate who's been hiding out for two decades, to lead a colossal revolt against all the human oppressors. J. Lee Thompson (The Guns of Navarone) directs this spectacular fourth installment of the Apes sci-fi series; Ricardo Montalban, Don Murray, Natalie Trundy and Hari Rhodes co-star.