Fast forward 20 years with Caesar, the son of Cornelius, alive and hidden all this time in a zoo. Now humans use apes as servants, pets and work in menial jobs until they retaliate against humans for poor treatment. Most humans in 1991 appear to be employed in security to beat misbehaving apes. I must say, using Roddy McDowell to also voice Caesar as well as his father, Cornelius, in the previous films was confusing. Same themes explored here in race relations and treatment of animals.