In this sequel to planet of the apes astronaut brent james franciscus is on a special mission to rescue george taylor charlton heston teaming up with taylors mute former comapnion nova linda harrison brent travels to the ape village where he was imprisoned after meeting dr zira kim hunter brent learns that taylor was last seen in the forbidden zone he sets off in pursuit and discovers that his colleague has been taken prisoner by an underground society of telepathic mutant hum