Mayor Sullivan of the humans finally gives birth to her child, though it may be that he's a "Silent", one of the new breed of humans who are unable to speak. He's taken by Ape Ruler Alaya, a chimpanzee, presumably to be raised by her. Her army of apes had pretty much defeated the human population and driven them out of the city of Mak. She wants to keep them hopeless, so they can never be powerful again. In the meantime, there's a group of renegade humans who have taken over one of the Ape's blimps--and they are on a crash course to the City Tree. Let's say their journey ends explosively...
As with much of the Ape stories, this reflects the time in which it was made,so in this story line there's lots of "terrorist" type scenarios with the humans and the blind-sidedness of the Apes. Continuity-wise it's 500 years in the future, though it does conflict with Doug Moench's TERROR ON THE PLANET OF THE APES storyline featured in Marvel's PLANET OF THE APES magazine from the 70's...