Tantor drinks water from the river and gets ill. Tarzan, Jane, and the Professor go upstream to find out what's poisoning the river while Terk tries to save Tantor. Along the way, they lose their boat and get captured by a group of natives who blame them for poisoning the river.

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.

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.