Ornithologist Professor Inigo Tinkle tells a less-than-enraptured audience about his most recent expedition to Africa in search for the Oozlum bird, which is said to fly in ever decreasing circles until it disappears up its own rear end. Financing the expedition is Lady Evelyn Bagley and the team are led by the lecherous Bill Boosey and his African guide Upsidasi. Also on the expedition is Tinkle's assistant, Claude Chumley and June, Lady Bagley's maidservant. Soon after the journey starts, a gorilla terrorises the campsite, and the travellers realise they have ventured into the territory of the "Noshas", a tribe of cannibals.




On the first night of the expedition, Lady Bagley reveals that she joined the expedition to find her long-lost husband and baby son who vanished twenty years ago on their honeymoon, whilst out on a walk. Her husband is believed to be dead, but she hopes to find her son Cecil's nappy pin as something to remember him by. Watching them from the bushes is Ug, a white jungle dweller that wears a loincloth and sandals. The next day, June stumbles across an oasis where she saves Ug from drowning and the two fall in love.




That night, Ug wanders into Lady Bagley's tent (mistaking it for June's), and she is astonished to see that Ug wears Cecil's nappy pin. Ug, who turns out to be Cecil, flees in fear while Lady Bagley faints with shock. The next day, the travellers are kidnapped by the Noshas. Intending rescue, Ug accidentally catapults himself into the Nosha camp and starts a fire. In the chaos, Ug, June and Upsidasi escape. However, the enraged Noshas apprehend the other travellers and prepare to kill them.




As they wait to be put to death, they are rescued by the all-female Lubby-Dubby tribe led by Leda from the Lost World of Aphrodisia. They are taken to Aphrodisia and meet the king of the tribe Tonka who turns out to be Walter Bagley, who was taken by the Noshas years ago, but saved and brought to Aphrodisia by the tribal women. Evelyn Bagley is infuriated that he never bothered to search for Cecil and laments she has seen him but has once again lost him. June and Ug are actually living happily together and June is teaching Ug to speak English.




Bill Boosey, Tinkle and Chumley enjoy the attention given to them by the tribal women, and Tinkle and Chumley are stunned to find that the Oozlum bird is in fact a sacred animal to the Lubby-Dubbies. Meanwhile, the Lubby-Dubbies need the menfolk to save themselves from extinction, as no males have been born in Aphrodisia for over a century. The men think their dreams have come true, until Leda makes it clear that the Lubby-Dubbies have no intention of letting them go. Tonka implies that the last man who tried to escape Aphrodisia was murdered by the tribe.




Lady Bagley is resentful of this work the men have been given and taking over control from her husband, ensures the mates assigned to them are the tribe's least attractive women. Three months later, the men are fed up, while Leda is outraged that nobody has got pregnant. She eventually overthrows Tonka, threatening harm to the men. Upsidasi arrives disguised as a woman, saying he has brought soldiers to save them. Ug and June also search for their friends and Ug summons a stampede of animals to create chaos and enable the men to get away. During the confusion, Tinkle snatches the Oozlum bird, and the team escape along with Tonka. After the chaos, Leda and her army chase after the men, but are more interested in the trampled soldiers. She says to let the others go not needing them now that they have "some real men." Lady Bagley is reunited with Ug, and the group return to England. Tinkle unveils his Oozlum bird to his audience, only to find it has apparently vanished up inside itself. June and Ug are happily married with a baby and live in a treehouse in the suburbs whilst Ug goes to work in a bowler hat, suit, and no shoes.