This screenplay by Adam Rifkin, is a direct-sequel to the very first Apes movie (1968), as if none of the other movie sequels happened. Cornelius is raising his young son. Zira is dead. Taylor is living out in the Forbidden Zone, teaching the wild humans to speak. When Cornelius is banished from Ape City his son is taken by the gorilla general Izan and raised as a warlike gorilla, Pax. In the Forbidden Zone Cornelius comes across Taylor and his son. When Taylor is killed he raises his human son, Duke. Eventually, they go back to Ape City and there's a confrontation between the humans and the gorillas who are now in power.
This has more of the "feel" of the Planet of the Apes" television series and is an interesting "alternate reality" version of what could have happened in the Apes Universe, if nothing else.