Ape City is in a panic. Word has spread of the capture of a talking human (Hal) and his bizarre alien companion (Sinestro). What's worse, a group of strange, scarred humans ("Mutants”) are spotted in The Forbidden Zone, being led by a strange-acting Cornelius, who's wearing a ring - a ring Sinestro has long been searching for.
As Cornelius loses himself to the ring, Doctor Zaius and Sinestro uncover a grave truth about the Planet of the Apes. With Hal Jordan, Zira, and Nova on the hunt through the Forbidden Zone, Kilowog, Guy Gardner, and Arisia bring reinforcements.