Tarzan is bitten by a poisonous spider and the gang must go to the top of the waterfall to find the antidote. Meanwhile, Terk is having a hard time getting used to Jane.

A trade manager named Renard Dumont makes his trading post where the rhino herd is, causing them to move into gorilla territories. Will the gorillas have to move?

Two leopard men take the Professor to the forgotten city of Opar, where Queen La is hoping for a king. She refuses the Professor and has the leopard men do what they wish with him. When Tarzan and the others find out, they all head for Opar, just in time to save the Professor. However, after seeing Tarzan, La falls in love with him and plans to get rid of Jane.

Tarzan and Terk find an injured gorilla named Gobu in the forest. Little do they know, but he is under orders from his leader to lure Tarzan back to Gobu's family. Once the injured gorilla (who Terk has taken a strong shine to) is better, he and Tarzan embark on the long journey to Gobu's home, only to find the evil Tublat, a bull ape who was expelled from Kerchak's family many years before, was waiting there to trap him. Meanwhile, Jane and the Professor attempt to teach Terk to be more lady-like.

The Professor eagerly awaits the arrival of a Doctor Doyle. Upon arrival, everyone is surprised to find that Doyle is actually a woman. Doctor Robin Doyle had come to Africa to study Keewazi's tribe with the Professor. While studying, they find some of the older men to have quite startling ages (from 500 to 700), and learn about a great fountain. The professor, who feels he's too old for Robin, secretly sets forth to find this fountain.

Doctor Robin Doyle returns to the jungle with her nephew Ian, a bookish child with few friends who spends his time collecting butterflies. While Robin and the Professor spend some quality time "spooning", the task of entertaining Ian falls to Tarzan, whom Ian sees as a much-needed role model. Lacking any other experience, Tarzan fills the day with activities he enjoyed as a child, and it's not long before the boy has discarded his formal trappings for a loincloth. None of this sits quite well with Jane, who worries about the dangers of a small child swinging recklessly from tree to tree—and what the good doctor will say when she finds out.

Disgusted by the decay near the elephant territory, Jane tries to use an English vine to cover up the scent. But the vines cover up everything and are too poisonous to eat. While Jane and the Professor try to think of a solution, Tarzan invites the elephants to live with the gorillas, but how long can they live together in harmony?

Tarzan's leadership of the gorilla family is challenged by a young silverback male named Moyo. Moyo wins leadership only when Tarzan sacrifices his in the fight in order to save Moyo's life. The new leader leaves with the gorillas to escape the threat of Histah, a giant python that used to terrorize the gorillas when Kala was young, leaving Tarzan to choose what's dearest to him—Jane or the gorillas.

Tantor starts believe in an "All-seeing elephant" that protects him after he survives series of dangerous accidents. Tantor decides to journey to Mount Indigo, where the all-seeing elephant supposedly lives, to prove his friends the elephant truly exists. Tarzan, Jane, Terk, and the Professor decide to accompany Tantor to make sure he stays safe.

Count Nikolas Rokoff hears about a treasure in the valley of the leopards and plans to find it. Tarzan doesn't want to help, until Rokoff threatens to hurt Jane if he doesn't.

Tarzan and Jane attend the wedding of Basuli and Naoh in the Waziri village. As part of the wedding ritual, Basuli must find and return with an eagle's feather. He is allowed a companion and he chooses Tarzan. Their quest is filled with setbacks and Basuli claims that fate is against them. Tarzan, however, suspects sabotage.

A bush pilot named Bobby Canler, who is an old friend of Jane, comes to visit her, but Tarzan senses something bad about him. He is later convinced he's just jealous so he backs off. Unfortunately, Tarzan was right.