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.

The Professor and Jane figure out that it's a mine that's poisoning the river and that Tarzan and the native warrior are in trouble. Tantor, Terk, Jane and the Professor come up with a plan and must work together with the natives to save Tarzan and get rid of the mine once and for all.

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.

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?