Renard Dumont arrives in Africa and begins building a trading post. In the process of building his post he has displaced the rhinos and they have moved into gorilla territory. Tarzan attempts to explain this to Dumont but he cares little for the problems of others. The rhinos refuse to leave or share the territory with the gorillas and Tarzan must find a solution to this dilemma before the gorillas are forced to relocate.
Jane's father, Professor Porter, is kidnapped by leopards. When Tarzan tries to rescue him he meets Queen La and her forgotten City of Opar. She likes him and tries to kill Jane to win his love. Then she asks him to chose between herself and Jane. He refuses to love her so she wants to kill them all. When everyone thinks that Jane has died she comes back to rescue Tarzan and the others.
Baruti and Jamila, an elephant couple, migrate into Tantor's herd to protect their hypochondriac son, Jabari (who bears an uncanny resemblance to the young Tantor), from the mad rampages of Mbaya, an elephant gone "rogue". Tantor and Jabari instantly bond, but, through a series of coincidences (including Jabari's insistence that African violets -- which Tantor's eaten for years -- are the dietary root of rogue behavior), Tantor comes to believe that he's responsible for Mbaya's recent rampage through Tarzan's protectorate (which he's somehow managed to sleep through) ...
Tantor falls ill after drinking from the river and the Professor concludes the water must be contaminated. Terk tends to the sick Tantor while Tarzan, Jane and the Prof. begin a perilous journey upriver to find the source of the contamination. Things go from bad to worse when they are captured by a tribe who suspects they may be the ones who have poisoned the river.
Terk and Tarzan save a gorilla from a pack of hyenas and bring him back to their home. Terk tries to become a "lady" to win this new gorilla's affection but this new ape has a dark secret as he is working for an old enemy of Tarzan's.
The Professor eagerly awaits the arrival of a Professor Doyle. Upon arrival, all are surprised to find that he's... a she? Professor Robin Doyle had come to Africa to study Keewazi's tribe with the Professor. While they study, they find some of the older men to have quite startling ages (from 500 to 700), and learn about a great fountain. Professor, who feels he's too old for Robin (he likes her), secretly sets forth to find this fountain.
Academic rival Samuel T. Philander, whose career has been made by stealing from Jane's father, comes to Africa to find out what Professor Porter is working on. This leads Tarzan to showing Jane and Prof. Porter the way to Pellucidar, the lost world beneath the Earth where dinosaurs still roam.
Tantor and Terk accompany the Prof. on an expedition to study giant flora and their clumsiness almost ends in disaster. Tantor wants to confess but Terk prefers covering up the truth. The prof. does manage to collect some plant liquid from the giant flowers which Terk promptly spills onto some beetles making them grow to gigantic proportions. Terk still tries to hide his and Tantor's involvement. It's not long before the beetles are on a rampage of destruction.
Tarzan and Jane are returning home from visiting the Waziri Village via a river boat piloted by Hugo and Hooft. When they land they notice that Dumont's trading post is really growing and modernizing. They also notice that the jungle is eerily quiet with no animal sounds to be heard. When they return home they find the tree house is in shambles as is the professor's camp and he has disappeared. Terk and Tantor burst into the camp complaining of a ringing in their heads and acting violently. Soon Tarzan and Jane are on the run for their lives as all of the jungle ...
To make the jungle more aromatic Jane introduces a plant not indigenous to Africa, this leads to an explosion of this new plant which results in the destruction of the elephants food source. Tarzan offers to let the elephants eat in gorilla territory until Jane and her father come up with a way to get rid of this new plant infestation, but while they wait tensions mount between the gorillas and elephants who are not use to sharing.
Samuel T. Philander is at it again, and wants to scoop another one of Professor Porter's jungle discoveries to pay off his Briotish creditors. This time he finds out about the healing Silver Ape, Mangani, which he captures in a cage. When Tarzan and Professor Porter attempt to rescue the ape from Philander's ship, Mangani proves his healing abilities in a miracle for Tarzan.
loggers are destroying the jungle near Tarzan and the family. The loggers are following the orders of Bob Markham who has the legal logging rights for this particular area of jungle. Tarzan confronts Markham and finds him to be a reasonable, family man with a daughter. They try to find a compromise but it doesn't quite hold and the logging continues. Tarzan is determined to protect his jungle but won't need to because the loggers begin to get sick and the professor fears he knows why...all the disturbing of the soil has released a dormant virus into the air. Tarzan ...
Hollywood comes to the jungle. When the director of a "Savage Jungle Man" movie sees the real Tarzan in action he's eager to dump leading actor Stanley Obrowski for the real deal. Jealously turns the jungle red with danger.
While playing with Tarzan Terk sees something that frightens her. She tells the others it was a scaly, green monster but the others are skeptical. Later, when Tarzan and the Prof. find a dead leopard they know Terk may be on to something. It appears that a Velociraptor from the underground world of Pellucidar has somehow made it to the surface and it's heading straight for the tree house.
A schooner is sinking and on board are Jane's Friends Greenley, Eleanor, Hazel and Greenley's fiancée Henry. Eleanor and Hazel do not think Henry is very 'well rounded' and hope exposing him to Tarzan can toughen him up. His bravery and manliness is put to the test when they are swept away by a tidal wave.
Nefarious villain Nicholas Rokoff brings his henchmen to Africa in search of pirate treasure, but when he learns that the Valley of the Leopard is too dangerous for and his men he kidnaps Jane to force Tarzan to retrieve the loot.
Jane is possessed by the disembodied spirit of Queen La. She dupes Dumont into escorting her to the City of Opar where she uses magic to rebuild it. Tarzan, with the help of elderly Usula, sets out to stop her evil plans.
Philander goes to Africa with the two British thugs to capture "Tarzan: The Missing Link" in an effort to pay off the thugs. While there they meet up with Prof. Porter, who's wearing a loincloth, and Philander attempts to convince the thugs that Porter is Tarzan.
Hugo & Hooft are developing a Barbecue sauce named Hugo and Hooft's Jazzy Jungle Barbecue Sauce. They don't count on Col. Staquait hearing of this and realizing that they are still alive. He sets out to trap them and deal with Tarzan if he gets in the way. Hugo and Hooft are sentenced to hard labor at Cape Doom an isolated French Foreign Legion prison. Tarzan is determined to free them but his attempt fails and he too is imprisoned.
Tarzan and Jane are invited to the Waziri village for the wedding of Basuli and Naoh. It is the custom of the Waziri that the groom face a challenge to prove his worthiness. Basuli must journey to a tall mountain and bring back an Eagle's feather. He is allowed to take one person with him and he chooses Tarzan which angers Muviro. Their journey is fraught with hardships and Tarzan begins to wonder if someone else isn't interfering.
Zutho, a Mandril monkey visits Tarzan and gets him to come with him. Tarzan reluctantly does so and Jane is perplexed as to why Tarzan would go. Tantor tells Jane a story of a young Tarzan, Tantor and Terk and their adventure on the forbidden side of the river and their first meeting with Zutho and what his strange hold over Tarzan is.
Following the Profesor's latest (unsuccessful) attempts to make tea, he goes to the trading post to try to persuade Dumont to trade something for a box of Earl Grey. Dumont obliges, when Jane persuades him that 'a good deed can be its own reward', which Tarzan overhears her saying. As they are about to leave, none other than those less-than-friendly-diamond-miners, Neils and Merkus arrive. They want to search for their lost diamonds, and Tarzan reluctantly allows them on the condition that they leave the gorilla family alone. While mining, Neils and Merkus are ...
Tarzan is duped by Lady Waltham into guiding her on a photographic safari. While on the safari Tantor, Terk, the Professor and Jane are all kidnapped and placed in deadly traps. She believes Tarzan is responsible for her brother Clayton's death and she wants revenge. She injects Tarzan with a poison and he has a fateful choice to make...save himself or his family.
A writer named Ed is in desperate need of some inspiration for his next novel. He finds it while walking down the street in the form of a newspaper article about Tarzan,The Missing Link. Ed has the inspiration he needs and begins tracking down various leads to Tarzan's whereabouts...including Samuel T. Philander, Hugo and Hooft and Renard Dumont. They all tell Ed of their first encounters with Tarzan. Ed heads out into the jungle to find Tarzan himself.
A violent thunderstorm has Tarzan, Jane and the rest of the gorilla family seeking shelter in nearby caves. Along the way Tarzan feels unsure that he can protect the family as well as Kerchak did. When they reach the cave they think they are safe but they have chosen the same cave that banished gorilla Tublat lives in. Tarzan is no physical match for Tublat and must use his superior cunning and ingenuity to defeat him.