The fourth in the Planet of the Apes series of films
picks up a few years after Zira and Cornelius gave birth to the
talking Ape, Milo, in Escape From The Planet of the Apes.
The year is now 1990 (!) and a plague has killed all cats and
dogs on earth. As a result, apes have been domesticated as pets
and, when found to have a superior intelligence, are put to work
as janitors, waiters and menial labourers.
Having been raised by Armando (Montalban) in his circus, the
young talking chimpanzee now sets about leading his fellow apes in
revolt against the humans who have enslaved them.