Jane's friends, Eleanor, Greenly, and Hazel, thinking Jane is in trouble, come to rescue her. When they find her and everything is explained, they fret Jane has changed. To prove she hasn't, Jane takes them on a picnic in the jungle. That's when trouble comes up.

Two sneaky men named Johannes Niels and Merkus come and want Tarzan to take them to the volcano on the other side of the jungle to look for diamonds. Tarzan agrees as long as he gets a diamond for Jane in return. Little does he realize that the men are not planning to keep up their side of the bargain when the diamonds are collected—or that his friends are following them.

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.

Poachers arrive in the jungle and are setting traps everywhere, so Tarzan warns everyone to be careful. Meanwhile, Terk encourages Tantor to act on his attractions to a female elephant named Dania with a talent for singing. The first date goes well, and though everybody finds Dania perfectly charming, she herself gets off on the wrong foot with Terk. When Terk discovers Tantor would rather spend his time with Dania than her, she plans to break them up, but ends up getting caught in one of the poachers' traps instead. Now Tantor must decide which is more important to him—his relationship with the difficult Dania, or saving his best friend from being kidnapped.

When Terk and Tantor accidentally spill some of the fluid from the giant flowers the Professor was studying onto a few beetles, it makes them giant themselves. To stay out of trouble, they keep it a secret. But how can you keep a couple of huge beetles a secret?

A film crew arrives in the jungle to shoot an action movie. Tarzan, being unaware of this, interferes in the process, causing him to appear in the scenes unintentionally. The film's male lead actor becomes jealous after being replaced by Tarzan and attempts to destroy the footage, causing a huge fire at the trading post.

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.

Tarzan helps the people on an sinking schooner escape. He discovers the passengers are Jane's friends Eleanor, Hazel, and Greenly, as well as Greenly's fiancé Henry. Eleanor and Hazel do not think Henry is "well-rounded" enough, hoping the jungle and Tarzan can toughen him up. Eventually Henry's toughness is put to the test when an earthquake, followed by a tidal wave, hits the jungle.

Hugo and Hooft use Tarzan to help them gather special ingredients for their hot sauce. The sauce, with the guys' names on the bottle, becomes popular to the French Foreign Legion, and is brought to the attention of Lt. Col. Staquait. Staquait vows to re-capture Hugo and Hooft for deserting, and succeeds eventually, resulting in the duo being sent to the Cape Doom prison. Upon attempting to free his friends, Tarzan is also captured. Jane attempts to contact the Magistrate to free Hugo and Hooft legally.

Johannes Niels and Merkus return to the jungle to mine diamonds. Tarzan agrees to this as long as they stay away from the gorillas. Niels and Merkus are threatened by Tublat, who they capture and plan to make money out of him. Tarzan sets out to free Tublat, despite Terk's protests and the past conflict between them.

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". He begins tracking down various leads to Tarzan's whereabouts, including Tarzan's friends and enemies. They all tell Ed of their first encounters with Tarzan, prompting Ed to head out into the jungle to find Tarzan himself.

Zutho, a shady mandrill from Tarzan's past, resurfaces, demanding a favor he claims is owed for keeping a 20-year-old secret. This results in Tarzan having to do everything Zutho tells him to. What secrets does Zutho know to gain such a hold over the lord of the jungle?

Baruti and Jamila, an elephant couple, migrate into Tantor's herd to protect their hypochondriac son, Jabari, from the mad rampages of Mbaya, an elephant gone "rogue". Tantor and Jabari instantly bond, but through a series of coincidences, Tantor comes to believe that he's responsible for Mbaya's recent rampage through Tarzan's protectorate and retreats into the jungle. Meanwhile, Jane attempts to discover something that Tarzan's afraid of.

Terk gets scared when she sees a monster, which is later revealed to be a velociraptor from Pellucidar. The others initially dismiss Terk, but believe her after the dinosaur attacks the Professor's camp as well as Tarzan and Jane's treehouse. Tarzan attempts to find out how the velociraptor managed to get out of Pellucidar and how it can be sent back.

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?

The Professor learns about a spiritual silver ape that, supposedly, cures the injured of the jungle. Not believing this is a spiritual creature, he plans to study it more. But when Philander steals his notes and finds out about the ape, he plans to capture it.

While the gang is setting up a surprise croquet game for the Professor, Jane encounters an ill-looking fawn. Upon touching the fawn, the soul of Queen La enters her body. Failing to return to Opar by herself, La turns to Tarzan, who senses something wrong right away. Instead, she turns to Dumont for help. Can the aid of Usula, the Waziri elder, bring Jane back before La retrieves her staff and brings Opar to life again?

Philander returns to Africa with two British thugs to capture "Tarzan: The Missing Link" in a last-ditch effort to pay off the thugs. While there, they meet up with the Professor and Philander attempts to convince the thugs that the Professor is Tarzan.

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.

Two deserters of the French Foreign Legion called Hooft and Hugo flee into the jungles of Africa. Unfortunately, their former superior, Lt. Colonel Staquait, finds their tracks and vows to follow them to the ends of the earth. Tarzan rescues the deserters from the perils of the jungle and the duo begin taking advantage of the resulting hospitality. Jane, being suspicious of the parasitic pair and their fantastic stories, decides to turn them in, only to realize who the real criminal is.

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.

Tarzan and Jane return from a trip to the Waziri village to find the Professor missing and his camp in ruin. Jane momentarily fears the worst, but soldiers on with Tarzan in an attempt to determine her father's whereabouts and condition—a pursuit impeded by the hordes of apparently mad animals, including Terk and Tantor, destroying everything in their path and pleading for the cessation of a mysterious, unheard ringing.

The arrogant and aggressive heavyweight boxing champion "One Punch" Mulligan, along with his manager and personal journalist, visit the jungle while on safari. When Tarzan accidentally knocks One Punch out cold, the boxer is mortified and demands a "rematch", which Tarzan refuses. However, One Punch is stubborn and looks for a way to provoke Tarzan into a fight.

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.