Amateur pilot Dick Penrod is flying his friends, jaded socialites Carl Kraski and Gamage Dean, and society columnist "Doodles" Fletcher to Cairo for a wedding, when his wife Diana bitterly remonstrates him for his expensive habits. As their argument escalates, Diana promises to seek a separation from Dick upon returning home. While flying low to impress his guests, Dick hits a flock of migrating flamingos forcing the plane to crash-land in the jungle. Tarzan, a native of the jungle, accompanied by his pet chimpanzee Cheta, swings across the jungle floor to the crash site, where the plane is precariously balanced on a steep cliff ledge. Tarzan helps each passenger to safety, but then mysteriously disappears. When a curious Diana goes in search of their savior, Opar tribesmen capture her. Alerted by Diana's screams, Tarzan returns to fight off the men, who attempt to drown Tarzan in a nearby waterfall. Tarzan prevails in the fight, but by the time he returns to shore, the Opar have fled with Diana. Dick and the other passengers, having followed Diana's screams to the waterfall, find Tarzan, who tells them the vicious tribe will sacrifice her. With no time to waste, Tarzan orders the group to remain there while he finds Diana. Meanwhile, villainous hunter "Tusker" Hawkins meets the Opar tribesmen on a trail and suggests he might provide them with more human sacrifices if they give him the unconscious Diana. When she comes to, Diana, unaware of the deal, is grateful for Hawkins' escort back to her husband and friends. When Tarzan finds that Diana is safe, he goes to the crash site to gather supplies. By sunset, Hawkins warns the group that despite their mayday call before the crash, authorities have little chance of finding them and suggests that they follow him to the coast where they can find safe passage to Nairobi. When Tarzan arrives, Hawkins explains that he will take them through the gorge near Eagle Mountain, but a suspicious Tarzan warns that the route is too near the Opar village. The next morning, as baboons, rhinoceros and water fowl awaken in the vast jungle, Tarzan catches river fish with his bare hands for the group's breakfast. After Gamage and Diana admire the wild man's physique from afar, Diana joins Tarzan for a swim. Meanwhile, Hawkins secretly makes plans with Opar tribesmen to meet them at the gorge to abduct the travelers. Back at the river, a crocodile is about to attack Diana when Tarzan uses a knife to kill the beast. As the group gathers near the fire for breakfast, a drunken Cheta, having retrieved liquor from the plane, wanders into the camp draped in Gamage's mink coat. After Tarzan agrees with Hawkins that they must leave the area, he makes mink moccasins from the coat and gives them to Diana and Gamage as replacements for their high-heeled shoes. With Tarzan as their leader, the group begins trudging through the jungle. While making camp that night, Hawkins takes Diana aside and tries to entice her to stay with him by revealing that he will soon be rich from selling the valuable Opar ivory tusks, but Diana rejects him. Later that night, Tarzan explains to the curious group that when his family was killed years ago, a mother ape raised him. He later learned to walk on two legs and made friends with missionaries, who taught him English. The next day as the group continues through a swamp, Tarzan senses that the Opar tribesmen are secretly following them. That night as the others sleep, Tarzan guards the camp's perimeter, where a sleepless Diana finds him. While Diana and Tarzan are talking about the difference between jungle and civilized "mates," Tarzan warns that although Hawkins appears to be kind, his heart is "black." When Tarzan finds an Opar spy dead from a lethal spider bite nearby, he orders the group to break camp and continue their journey through the night. The following morning the group finds the gorge blocked. Noting signs of a flood, Tarzan accuses Hawkins, who claimed to have recently traveled through the gorge, of lying. Grabbing Hawkins' guns, Tarzan hands them to Carl and Dick and leaves to find an alternate route out. In his absence the Opar, with Hawkins' help, attack and capture the group, taking them through an underground passage to their village. Upon returning to the gorge, Tarzan deduces that his friends have been captured and tracks the tribe through the passage. Once on the other side, Tarzan hands one of the travelers' cigarette lighters to Cheta and sends him ahead to the village. Opar tribesmen soon find Tarzan and attack, but Tarzan prevails. At the village, the tribe is performing a ceremonial dance in preparation for the sacrifice of their captives. All the prisoners are all tied to pyres except for Diana, who, along with the ivory tusks, is Hawkins' prize for trapping the group. Suddenly, distant talking drums played by Tarzan inform Chief Ogonooro that Tarzan has been captured and that Hawkins has betrayed the chief and plans to burn the Opar village. Meanwhile, Cheta uses the lighter to set fire to the village, causing havoc among the tribespeople. Tarzan then swings across the cliffs on a vine, frees his friends and shows them to a rope bridge, over which they escape. Tarzan and Hawkins are crossing just as tribesmen cut the bridge, leaving both men dangling high above a precipice. The chief kills Hawkins with a spear, while Dick helps Tarzan to safety. Dick then promises Diana that if they return alive, he will never buy another plane. The next morning, the group waves goodbye to Tarzan as they continue on their last leg of their journey back to civilization.
