Returning to Cathne, Tarzan and the Cathnians find the city under siege by Terribs. More help for Cathne arrives in the form of the Gallugos, looking for a new home. The siege is lifted and Tarzan helps the Gallugos select a new site for their city, with the approval of Cathnian king Jathon.; When hunters discover a mangani wearing a ruby necklace, they become obsessed with killing other mangani for jewelry. The apes had found a pirate's treasure chest and were wearing the jewelry from it. They were also fighting each other over the treasure. Tarzan takes the jewelry from the mangani and gives it to the hunters who begin to fight among themselves.; Ungali, the former witch doctor of the Matusis, frames Boy for the theft of King Atumbo's throne stool. Boy is kidnapped by the Matusis and forced to undergo trial by mamba. Tarzan arrives in time to take Boy's place and using the same trickery as Ungali, passes the trial.; Dan-El and Natongo free Mothibi from Ulgo's guards and then capture the bulk of Ulgo's army.