Abbott and Costello search for an African diamond mine.

In Klopper's department store in New York City, salesmen Stanley Livington and Buzz Johnson are each approached by separate parties about a book, Dark Safari , which contains a map of diamond mines in the Congo. Although the book is out of print, Stanley swears he recalls the map's details and agrees to copy it for Grappler McCoy and Boots Wilson for a large sum of money. Unknown to Stanley, Buzz has arranged for him to copy the map for wealthy Diana Emerson later that evening for even more money. Grappler and Boots are Diana's henchmen, and when Buzz and Stanley arrive at her estate, Buzz overhears them planning an expedition with famous explorer Clyde Beatty. When Buzz learns how much Diana is paying Beatty, he negotiates higher terms for Stanley's map copying services, insisting that both go along on the safari. Diana reluctantly agrees, for although she tells everyone involved she is searching for the rare orangutan gargantuan, she actually hopes to find an enormous diamond mine to which the map is key. Once in Africa, Buzz discovers Stanley never knew anything about the legitimate map, and to stall, they pretend to be guides, leading the group further into the interior. En route, Stanley meets big game hunter Frank Buck, who is genuinely seeking the orangutan gargantuan. When Stanley accidentally frees the orangutan from one of Buck's traps, the beast is grateful and becomes attached to him. After some near mishaps with crocodiles and lions, Stanley and Buzz stumble across the diamond mine and realize it has been Diana's goal all along. A group of cannibal natives then kidnap Stanley and Buzz, taking them back to their village as food. The orangutan frees Stanley and once back at camp, Buzz bullies Diana into cutting Beatty, Boots and Grappler out of the deal. Meanwhile, the native chief and a group of his men come into the camp offering a huge bag of diamonds in exchange for the savory Stanley. Stanley and Buzz flee, pursued by both the natives and Diana's men. Buzz stops to hide his bag of diamonds, but when he runs into the orangutan he faints in fear, and the orangutan takes the diamonds. The orangutan them summons all the jungle monkeys to aid Stanley and Buzz and the garangutuan appears, frightening off the entire expedition. Back in New York a daper looking Stanley enters the towering new Livington building where Buzz works as the elevator man. Stanley goes up to the president's office and reports to his boss, the orangutan.