Tarzan and his friend, Chief Buto, discover that young men from Buto's tribe are poaching elephants. One of the young men, Numumba, has the backing of the local witch doctor, Kisambu. The witch doctor trains a chimp into throwing a spear, attacking Numumba. He then blames the attack on Tarzan and Buto. Tarzan finds the chimp, N'Kengo, presents him to the tribe and reveals the plot. The chimp and the witch doctor kill each other.